Heterologous versus homologous COVID-19 booster vaccination in previous recipients of two doses of CoronaVac COVID-19 vaccine in Brazil (RHH-001): a phase 4, non-inferiority, single blind, randomised study.

INTRODUCTION: The inactivated whole-virion SARS-CoV-2 vaccine (CoronaVac, Sinovac) has been widely used in a two-dose schedule. We assessed whether a third dose of the homologous or a different vaccine could boost immune responses. METHODS: RHH-001 is a phase 4, participant masked, two centre, safety and immunogenicity study of Brazilian adults (18 years and older) in São Paulo or Salvador who had received two doses of CoronaVac 6 months previously. The third heterologous dose was of either a recombinant adenoviral vectored vaccine (Ad26.COV2-S, Janssen), an mRNA vaccine (BNT162b2, Pfizer-BioNTech), or a recombinant adenoviral-vectored ChAdOx1 nCoV-19 vaccine (AZD1222, AstraZeneca), compared with a third homologous dose of CoronaVac. Participants were randomly assigned (5:6:5:5) by a RedCAP computer randomisation system stratified by site, age group (18-60 years or 61 years and over), and day of randomisation, with a block size of 42. The primary outcome was non-inferiority of anti-spike IgG antibodies 28 days after the booster dose in the heterologous boost groups compared with homologous regimen, using a non-inferiority margin for the geometric mean ratio (heterologous vs homologous) of 0·67. Secondary outcomes included neutralising antibody titres at day 28, local and systemic reactogenicity profiles, adverse events, and serious adverse events. This study was registered with Registro Brasileiro de Ensaios Clínicos, number RBR-9nn3scw. FINDINGS: Between Aug 16, and Sept 1, 2021, 1240 participants were randomly assigned to one of the four groups, of whom 1239 were vaccinated and 1205 were eligible for inclusion in the primary analysis. Antibody concentrations were low before administration of a booster dose with detectable neutralising antibodies of 20·4% (95% CI 12·8-30·1) in adults aged 18-60 years and 8·9% (4·2-16·2) in adults 61 years or older. From baseline to day 28 after the booster vaccine, all groups had a substantial rise in IgG antibody concentrations: the geometric fold-rise was 77 (95% CI 67-88) for Ad26.COV2-S, 152 (134-173) for BNT162b2, 90 (77-104) for ChAdOx1 nCoV-19, and 12 (11-14) for CoronaVac. All heterologous regimens had anti-spike IgG responses at day 28 that were superior to homologous booster responses: geometric mean ratios (heterologous vs homologous) were 6·7 (95% CI 5·8-7·7) for Ad26.COV2-S, 13·4 (11·6-15·3) for BNT162b2, and 7·0 (6·1-8·1) for ChAdOx1 nCoV-19. All heterologous boost regimens induced high concentrations of pseudovirus neutralising antibodies. At day 28, all groups except for the homologous boost in the older adults reached 100% seropositivity: geometric mean ratios (heterologous vs homologous) were 8·7 (95% CI 5·9-12·9) for Ad26.COV2-S vaccine, 21·5 (14·5-31·9) for BNT162b2, and 10·6 (7·2-15·6) for ChAdOx1 nCoV-19. Live virus neutralising antibodies were also boosted against delta (B.1.617.2) and omicron variants (B.1.1.529). There were five serious adverse events. Three of which were considered possibly related to the vaccine received: one in the BNT162b2 group and two in the Ad26.COV2-S group. All participants recovered and were discharged home. INTERPRETATION: Antibody concentrations were low at 6 months after previous immunisation with two doses of CoronaVac. However, all four vaccines administered as a third dose induced a significant increase in binding and neutralising antibodies, which could improve protection against infection. Heterologous boosting resulted in more robust immune responses than homologous boosting and might enhance protection. FUNDING: Ministry of Health, Brazil.

Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK.

BACKGROUND: A safe and efficacious vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), if deployed with high coverage, could contribute to the control of the COVID-19 pandemic. We evaluated the safety and efficacy of the ChAdOx1 nCoV-19 vaccine in a pooled interim analysis of four trials. METHODS: This analysis includes data from four ongoing blinded, randomised, controlled trials done across the UK, Brazil, and South Africa. Participants aged 18 years and older were randomly assigned (1:1) to ChAdOx1 nCoV-19 vaccine or control (meningococcal group A, C, W, and Y conjugate vaccine or saline). Participants in the ChAdOx1 nCoV-19 group received two doses containing 5 × 1010 viral particles (standard dose; SD/SD cohort); a subset in the UK trial received a half dose as their first dose (low dose) and a standard dose as their second dose (LD/SD cohort). The primary efficacy analysis included symptomatic COVID-19 in seronegative participants with a nucleic acid amplification test-positive swab more than 14 days after a second dose of vaccine. Participants were analysed according to treatment received, with data cutoff on Nov 4, 2020. Vaccine efficacy was calculated as 1 - relative risk derived from a robust Poisson regression model adjusted for age. Studies are registered at ISRCTN89951424 and ClinicalTrials.gov, NCT04324606, NCT04400838, and NCT04444674. FINDINGS: Between April 23 and Nov 4, 2020, 23 848 participants were enrolled and 11 636 participants (7548 in the UK, 4088 in Brazil) were included in the interim primary efficacy analysis. In participants who received two standard doses, vaccine efficacy was 62·1% (95% CI 41·0-75·7; 27 [0·6%] of 4440 in the ChAdOx1 nCoV-19 group vs71 [1·6%] of 4455 in the control group) and in participants who received a low dose followed by a standard dose, efficacy was 90·0% (67·4-97·0; three [0·2%] of 1367 vs 30 [2·2%] of 1374; pinteraction=0·010). Overall vaccine efficacy across both groups was 70·4% (95·8% CI 54·8-80·6; 30 [0·5%] of 5807 vs 101 [1·7%] of 5829). From 21 days after the first dose, there were ten cases hospitalised for COVID-19, all in the control arm; two were classified as severe COVID-19, including one death. There were 74 341 person-months of safety follow-up (median 3·4 months, IQR 1·3-4·8): 175 severe adverse events occurred in 168 participants, 84 events in the ChAdOx1 nCoV-19 group and 91 in the control group. Three events were classified as possibly related to a vaccine: one in the ChAdOx1 nCoV-19 group, one in the control group, and one in a participant who remains masked to group allocation. INTERPRETATION: ChAdOx1 nCoV-19 has an acceptable safety profile and has been found to be efficacious against symptomatic COVID-19 in this interim analysis of ongoing clinical trials. FUNDING: UK Research and Innovation, National Institutes for Health Research (NIHR), Coalition for Epidemic Preparedness Innovations, Bill & Melinda Gates Foundation, Lemann Foundation, Rede D'Or, Brava and Telles Foundation, NIHR Oxford Biomedical Research Centre, Thames Valley and South Midland's NIHR Clinical Research Network, and AstraZeneca.

Single-dose administration and the influence of the timing of the booster dose on immunogenicity and efficacy of ChAdOx1 nCoV-19 (AZD1222) vaccine: a pooled analysis of four randomised trials.

BACKGROUND: The ChAdOx1 nCoV-19 (AZD1222) vaccine has been approved for emergency use by the UK regulatory authority, Medicines and Healthcare products Regulatory Agency, with a regimen of two standard doses given with an interval of 4-12 weeks. The planned roll-out in the UK will involve vaccinating people in high-risk categories with their first dose immediately, and delivering the second dose 12 weeks later. Here, we provide both a further prespecified pooled analysis of trials of ChAdOx1 nCoV-19 and exploratory analyses of the impact on immunogenicity and efficacy of extending the interval between priming and booster doses. In addition, we show the immunogenicity and protection afforded by the first dose, before a booster dose has been offered. METHODS: We present data from three single-blind randomised controlled trials-one phase 1/2 study in the UK (COV001), one phase 2/3 study in the UK (COV002), and a phase 3 study in Brazil (COV003)-and one double-blind phase 1/2 study in South Africa (COV005). As previously described, individuals 18 years and older were randomly assigned 1:1 to receive two standard doses of ChAdOx1 nCoV-19 (5 × 1010 viral particles) or a control vaccine or saline placebo. In the UK trial, a subset of participants received a lower dose (2·2 × 1010 viral particles) of the ChAdOx1 nCoV-19 for the first dose. The primary outcome was virologically confirmed symptomatic COVID-19 disease, defined as a nucleic acid amplification test (NAAT)-positive swab combined with at least one qualifying symptom (fever ≥37·8°C, cough, shortness of breath, or anosmia or ageusia) more than 14 days after the second dose. Secondary efficacy analyses included cases occuring at least 22 days after the first dose. Antibody responses measured by immunoassay and by pseudovirus neutralisation were exploratory outcomes. All cases of COVID-19 with a NAAT-positive swab were adjudicated for inclusion in the analysis by a masked independent endpoint review committee. The primary analysis included all participants who were SARS-CoV-2 N protein seronegative at baseline, had had at least 14 days of follow-up after the second dose, and had no evidence of previous SARS-CoV-2 infection from NAAT swabs. Safety was assessed in all participants who received at least one dose. The four trials are registered at ISRCTN89951424 (COV003) and ClinicalTrials.gov, NCT04324606 (COV001), NCT04400838 (COV002), and NCT04444674 (COV005). FINDINGS: Between April 23 and Dec 6, 2020, 24 422 participants were recruited and vaccinated across the four studies, of whom 17 178 were included in the primary analysis (8597 receiving ChAdOx1 nCoV-19 and 8581 receiving control vaccine). The data cutoff for these analyses was Dec 7, 2020. 332 NAAT-positive infections met the primary endpoint of symptomatic infection more than 14 days after the second dose. Overall vaccine efficacy more than 14 days after the second dose was 66·7% (95% CI 57·4-74·0), with 84 (1·0%) cases in the 8597 participants in the ChAdOx1 nCoV-19 group and 248 (2·9%) in the 8581 participants in the control group. There were no hospital admissions for COVID-19 in the ChAdOx1 nCoV-19 group after the initial 21-day exclusion period, and 15 in the control group. 108 (0·9%) of 12 282 participants in the ChAdOx1 nCoV-19 group and 127 (1·1%) of 11 962 participants in the control group had serious adverse events. There were seven deaths considered unrelated to vaccination (two in the ChAdOx1 nCov-19 group and five in the control group), including one COVID-19-related death in one participant in the control group. Exploratory analyses showed that vaccine efficacy after a single standard dose of vaccine from day 22 to day 90 after vaccination was 76·0% (59·3-85·9). Our modelling analysis indicated that protection did not wane during this initial 3-month period. Similarly, antibody levels were maintained during this period with minimal waning by day 90 (geometric mean ratio [GMR] 0·66 [95% CI 0·59-0·74]). In the participants who received two standard doses, after the second dose, efficacy was higher in those with a longer prime-boost interval (vaccine efficacy 81·3% [95% CI 60·3-91·2] at ≥12 weeks) than in those with a short interval (vaccine efficacy 55·1% [33·0-69·9] at <6 weeks). These observations are supported by immunogenicity data that showed binding antibody responses more than two-fold higher after an interval of 12 or more weeks compared with an interval of less than 6 weeks in those who were aged 18-55 years (GMR 2·32 [2·01-2·68]). INTERPRETATION: The results of this primary analysis of two doses of ChAdOx1 nCoV-19 were consistent with those seen in the interim analysis of the trials and confirm that the vaccine is efficacious, with results varying by dose interval in exploratory analyses. A 3-month dose interval might have advantages over a programme with a short dose interval for roll-out of a pandemic vaccine to protect the largest number of individuals in the population as early as possible when supplies are scarce, while also improving protection after receiving a second dose. FUNDING: UK Research and Innovation, National Institutes of Health Research (NIHR), The Coalition for Epidemic Preparedness Innovations, the Bill & Melinda Gates Foundation, the Lemann Foundation, Rede D'Or, the Brava and Telles Foundation, NIHR Oxford Biomedical Research Centre, Thames Valley and South Midland's NIHR Clinical Research Network, and AstraZeneca.

Efficacy of the Herpes Zoster Subunit Vaccine in Adults 70 Years of Age or Older.

BACKGROUND: A trial involving adults 50 years of age or older (ZOE-50) showed that the herpes zoster subunit vaccine (HZ/su) containing recombinant varicella-zoster virus glycoprotein E and the AS01B adjuvant system was associated with a risk of herpes zoster that was 97.2% lower than that associated with placebo. A second trial was performed concurrently at the same sites and examined the safety and efficacy of HZ/su in adults 70 years of age or older (ZOE-70). METHODS: This randomized, placebo-controlled, phase 3 trial was conducted in 18 countries and involved adults 70 years of age or older. Participants received two doses of HZ/su or placebo (assigned in a 1:1 ratio) administered intramuscularly 2 months apart. Vaccine efficacy against herpes zoster and postherpetic neuralgia was assessed in participants from ZOE-70 and in participants pooled from ZOE-70 and ZOE-50. RESULTS: In ZOE-70, 13,900 participants who could be evaluated (mean age, 75.6 years) received either HZ/su (6950 participants) or placebo (6950 participants). During a mean follow-up period of 3.7 years, herpes zoster occurred in 23 HZ/su recipients and in 223 placebo recipients (0.9 vs. 9.2 per 1000 person-years). Vaccine efficacy against herpes zoster was 89.8% (95% confidence interval [CI], 84.2 to 93.7; P<0.001) and was similar in participants 70 to 79 years of age (90.0%) and participants 80 years of age or older (89.1%). In pooled analyses of data from participants 70 years of age or older in ZOE-50 and ZOE-70 (16,596 participants), vaccine efficacy against herpes zoster was 91.3% (95% CI, 86.8 to 94.5; P<0.001), and vaccine efficacy against postherpetic neuralgia was 88.8% (95% CI, 68.7 to 97.1; P<0.001). Solicited reports of injection-site and systemic reactions within 7 days after injection were more frequent among HZ/su recipients than among placebo recipients (79.0% vs. 29.5%). Serious adverse events, potential immune-mediated diseases, and deaths occurred with similar frequencies in the two study groups. CONCLUSIONS: In our trial, HZ/su was found to reduce the risks of herpes zoster and postherpetic neuralgia among adults 70 years of age or older. (Funded by GlaxoSmithKline Biologicals; ZOE-50 and ZOE-70 ClinicalTrials.gov numbers, NCT01165177 and NCT01165229 .).

Immune Responses to a Recombinant Glycoprotein E Herpes Zoster Vaccine in Adults Aged 50 Years or Older.

Background: The herpes zoster subunit vaccine (HZ/su), consisting of varicella-zoster virus glycoprotein E (gE) and AS01B Adjuvant System, was highly efficacious in preventing herpes zoster in the ZOE-50 and ZOE-70 trials. We present immunogenicity results from those trials. Methods: Participants (ZOE-50: ≥50; ZOE-70: ≥70 years of age) received 2 doses of HZ/su or placebo, 2 months apart. Serum anti-gE antibodies and CD4 T cells expressing ≥2 of 4 activation markers assessed (CD42+) after stimulation with gE-peptides were measured in subcohorts for humoral (n = 3293) and cell-mediated (n = 466) immunogenicity. Results: After vaccination, 97.8% of HZ/su and 2.0% of placebo recipients showed a humoral response. Geometric mean anti-gE antibody concentrations increased 39.1-fold and 8.3-fold over baseline in HZ/su recipients at 1 and 36 months post-dose 2, respectively. A gE-specific CD42+ T-cell response was shown in 93.3% of HZ/su and 0% of placebo recipients. Median CD42+ T-cell frequencies increased 24.6-fold (1 month) and 7.9-fold (36 months) over baseline in HZ/su recipients and remained ≥5.6-fold above baseline in all age groups at 36 months. The proportion of CD4 T cells expressing all 4 activation markers increased over time in all age groups. Conclusions: Most HZ/su recipients developed robust immune responses persisting for 3 years following vaccination. Clinical Trials Registration: NCT01165177; NCT01165229.

Efficacy of an adjuvanted herpes zoster subunit vaccine in older adults.

BACKGROUND: In previous phase 1-2 clinical trials involving older adults, a subunit vaccine containing varicella-zoster virus glycoprotein E and the AS01B adjuvant system (called HZ/su) had a clinically acceptable safety profile and elicited a robust immune response. METHODS: We conducted a randomized, placebo-controlled, phase 3 study in 18 countries to evaluate the efficacy and safety of HZ/su in older adults (≥50 years of age), stratified according to age group (50 to 59, 60 to 69, and ≥70 years). Participants received two intramuscular doses of the vaccine or placebo 2 months apart. The primary objective was to assess the efficacy of the vaccine, as compared with placebo, in reducing the risk of herpes zoster in older adults. RESULTS: A total of 15,411 participants who could be evaluated received either the vaccine (7698 participants) or placebo (7713 participants). During a mean follow-up of 3.2 years, herpes zoster was confirmed in 6 participants in the vaccine group and in 210 participants in the placebo group (incidence rate, 0.3 vs. 9.1 per 1000 person-years) in the modified vaccinated cohort. Overall vaccine efficacy against herpes zoster was 97.2% (95% confidence interval [CI], 93.7 to 99.0; P<0.001). Vaccine efficacy was between 96.6% and 97.9% for all age groups. Solicited reports of injection-site and systemic reactions within 7 days after vaccination were more frequent in the vaccine group. There were solicited or unsolicited reports of grade 3 symptoms in 17.0% of vaccine recipients and 3.2% of placebo recipients. The proportions of participants who had serious adverse events or potential immune-mediated diseases or who died were similar in the two groups. CONCLUSIONS: The HZ/su vaccine significantly reduced the risk of herpes zoster in adults who were 50 years of age or older. Vaccine efficacy in adults who were 70 years of age or older was similar to that in the other two age groups. (Funded by GlaxoSmithKline Biologicals; ZOE-50 ClinicalTrials.gov number, NCT01165177.).

Safe administration of rotavirus vaccine in a cohort of infants exposed to immunosuppressive drugs during gestation.

In utero exposure to immunosuppressive drugs might be a contraindication to rotavirus vaccine, but that may vary according to the immunosuppressive regimen. We evaluated 24 infants born to kidney transplanted mothers exposed to 3 immunosuppressants during pregnancy (prednisone, azathioprine, and tacrolimus or cyclosporine) and 31 control infants not exposed to these medications. No differences in adverse events were detected after rotavirus vaccination at 2 and 4 months.

Identification of Serologic Markers for School-Aged Children With Congenital Rubella Syndrome.

BACKGROUND: Congenital rubella syndrome (CRS) case identification is challenging in older children since laboratory markers of congenital rubella virus (RUBV) infection do not persist beyond age 12 months. METHODS: We enrolled children with CRS born between 1998 and 2003 and compared their immune responses to RUBV with those of their mothers and a group of similarly aged children without CRS. Demographic data and sera were collected. Sera were tested for anti-RUBV immunoglobulin G (IgG), IgG avidity, and IgG response to the 3 viral structural proteins (E1, E2, and C), reflected by immunoblot fluorescent signals. RESULTS: We enrolled 32 children with CRS, 31 mothers, and 62 children without CRS. The immunoblot signal strength to C and the ratio of the C signal to the RUBV-specific IgG concentration were higher (P < .029 for both) and the ratio of the E1 signal to the RUBV-specific IgG concentration lower (P = .001) in children with CRS, compared with their mothers. Compared with children without CRS, children with CRS had more RUBV-specific IgG (P < .001), a stronger C signal (P < .001), and a stronger E2 signal (P ≤ .001). Two classification rules for children with versus children without CRS gave 100% specificity with >65% sensitivity. CONCLUSIONS: This study was the first to establish classification rules for identifying CRS in school-aged children, using laboratory biomarkers. These biomarkers should allow improved burden of disease estimates and monitoring of CRS control programs.

Prevalence and Incidence of Respiratory Syncytial Virus and Other Respiratory Viral Infections in Children Aged 6 Months to 10 Years With Influenza-like Illness Enrolled in a Randomized Trial.

BACKGROUND: The high burden of respiratory syncytial virus (RSV)-associated morbidity and mortality makes vaccine development a priority. METHODS: As part of an efficacy trial of pandemic influenza vaccines (NCT01051661), RSV epidemiology in healthy children aged 6 months to <10 years at first vaccination with influenza-like illness (ILI) was evaluated in Australia, Brazil, Colombia, Costa Rica, Mexico, the Philippines, Singapore, and Thailand between February 2010 and August 2011. Active surveillance for ILI was conducted for approximately 1 year, with nasal and throat swabs analyzed by polymerase chain reaction. The prevalence and incidence of RSV among ILI episodes were calculated. RESULTS: A total of 6266 children were included, of whom 2421 experienced 3717 ILI episodes with a respiratory sample available. RSV was detected for 359 ILI episodes, a prevalence of 9.7% (95% confidence interval: 8.7-10.7). The highest prevalence was in children aged 12-23 or 24-35 months in all countries except the Philippines, where it was in children aged 6-11 months. The incidence of RSV-associated ILI was 7.0 (6.3-7.7) per 100 person-years (PY). Eighty-eight ILI episodes resulted in hospitalization, of which 8 were associated with RSV (prevalence 9.1% [4.0-17.1]; incidence 0.2 [0.1-0.3] per 100 PY). The incidence of RSV-associated ILI resulting in medical attendance was 6.0 (5.4-6.7) per 100 PY. RSV B subtypes were observed more frequently than A subtypes. CONCLUSIONS: Active surveillance demonstrated the considerable burden of RSV-associated illness that would not be identified through hospital-based surveillance, with a substantial part of the burden occurring in older infants and children.

Relative efficacy of AS03-adjuvanted pandemic influenza A(H1N1) vaccine in children: results of a controlled, randomized efficacy trial.

BACKGROUND: The vaccine efficacy (VE) of 1 or 2 doses of AS03-adjuvanted influenza A(H1N1) vaccine relative to that of 2 doses of nonadjuvanted influenza A(H1N1) vaccine in children 6 months to <10 years of age in a multinational study conducted during 2010-2011. METHODS: A total of 6145 children were randomly assigned at a ratio of 1:1:1 to receive 2 injections 21 days apart of A/California/7/2009(H1N1)-AS03 vaccine at dose 1 and saline placebo at dose 2, 2 doses 21 days apart of A/California/7/2009(H1N1)-AS03 vaccine (the Ad2 group), or 2 doses 21 days apart of nonadjuvanted A/California/7/2009(H1N1) vaccine (the NAd2 group). Active surveillance for influenza-like illnesses continued from days 14 to 385. Nose and throat samples obtained during influenza-like illnesses were tested for A/California/7/2009(H1N1), using reverse-transcriptase polymerase chain reaction. Immunogenicity, reactogenicity, and safety were assessed. RESULTS: There were 23 cases of confirmed 2009 pandemic influenza A(H1N1) (A[H1N1]pdm09) infection for the primary relative VE analysis. The VE in the Ad2 group relative to that in the NAd2 group was 76.8% (95% confidence interval, 18.5%-93.4%). The benefit of the AS03 adjuvant was demonstrated in terms of the greater immunogenicity observed in the Ad2 group, compared with the NAd2 group. CONCLUSION: The 4-8-fold antigen-sparing adjuvanted pandemic influenza vaccine demonstrated superior and clinically important prevention of A(H1N1)pdm09 infection, compared with nonadjuvanted vaccine, with no observed increase in medically attended or serious adverse events. These data support the use of adjuvanted influenza vaccines during influenza pandemics. Clinical Trials Registration. NCT01051661.

Egg allergy and yellow fever vaccination.

OBJECTIVE: Evaluate biomarkers capable of safely guiding Yellow fever vaccine (YFV) vaccination among individuals suspicious of hen's egg allergy, and identify factors associated with a higher risk for adverse events after immunization (AEAI). METHODS: Patients underwent skin prick test (SPT) for standardized allergens: whole egg, egg white, egg yolk; YFV (1:10 dilution; Biomanguinhos-Fiocruz), and intradermal test (IDT; YFV 0.02 mL, 1:100 dilution) and positive and negative controls. Serum levels of specific IgE (sIgE) for a whole egg, egg white, egg yolk, egg albumin, ovomucoid, lysozyme, and conalbumin (ImmunoCap®; ThermoFisher®) were obtained. Patients sensitized to YFV were submitted to YFV desensitization, and those negatives received YFV (0.5mL) and remained under surveillance for at least one hour. RESULTS: 103 patients were enrolled, 95% under 12 years old. 71% (81/103) of patients had reactions: 80% immediate, 11% mixed, and 9% delayed. There was an association between positive skin test results with YFV and the severity of the reaction (OR:7.64; 95%CI:1.61-36.32; p = 0,011). Only the presence of sIgE to ovomucoid was associated with clinical symptoms (p = 0,025). Thirty patients underwent the YFV desensitization protocol. CONCLUSION: There is a relationship between the positivity of the egg's components and the severity of the clinical reaction. Furthermore, the relationship between the positivity of the tests with the YFV and egg's components may show a tendency to look at ovomucoid and conalbumin, but it is not a certainty. Therefore, further studies are needed to confirm these associations, and for now, the authors still recommend using the vaccine for testing when necessary.

Interchangeability of different COVID-19 vaccine platforms as booster doses: A phase 3 study mimicking real-world practice.

BACKGROUND: The COVID-19 pandemic is over but the highly immunized or naturally exposed global population still requires booster vaccinations against newly emerging SARS-CoV-2 variants. We assessed safety and immunogenicity of booster doses of COVID-19 vaccines based on three different platforms in a setting that mimics the current routine practice in Brazil. METHODS: In this phase 3 study from 14 February 2023 to 12 June 2023 we enrolled previously immunized adults to receive an additional booster dose of one of three vaccines. Immunogenicity against ancestor SARS-CoV-2 and Omicron BF.7, BQ.1.1.3, and XBB.1.5.6 sub-lineages was measured as ELISA IgG or virus neutralizing (VNT) antibodies and safety/reactogenicity assessed using diary cards. RESULTS: Volunteers with a history of full primary COVID-19 immunization striated to three cohorts according to their previous booster vaccination history-0 (n = 26), 1 (n = 140) or 2 (n = 606) booster vaccinations-were randomized 2:1:1 to receive either recombinant protein (SCB-2019, Clover), adenovirus-vector (ChAdOx1-S, AstraZeneca/Fiocruz), or mRNA (BNT162b2, Pfizer/Wyeth). Baseline antibody titers were higher in individuals who had received one or two boosters and titers against both ancestor and Omicron sub-lineages increased in all groups regardless of the number of previous booster doses or the vaccine used. Day 28 geometric mean titers (GMTs) and geometric mean-fold rises (GMFR) against all variants were higher after BNT162b than SCB-2019 or ChAdOx1-S, but BNT162b groups displayed more rapid antibody waning at Day 84. Within cohorts each vaccine elicited similar GMFR against the different SARS-CoV-2 strains. All vaccines were well tolerated with similar solicited reactogenicity profiles. CONCLUSIONS: Protein, adenovirus-vector or mRNA vaccine boosters were equally well tolerated and immunogenic against ancestor SARS-CoV-2 and Omicron sub-lineages in fully primed adults with 0-2 prior boosters. BNT162b induced the highest immune responses but also the most rapid waning of antibodies 3 months after vaccination. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, identifier NCT05812586.

Pertussis antibodies and vaccination coverage among healthcare professionals in Brazil is inadequate: A cross-sectional serological study.

INTRODUCTION: Worldwide, tetanus-diphtheria-acellular pertussis (Tdap) vaccination coverage of healthcare professionals (HCPs) is below 40%, but this data is not available for Brazil. We hypothesize that a high number of HCPs are not immune to pertussis in Brazil. Main objective was to determine the seroprevalence of anti-pertussis toxin (anti-PT IgG) among HCPs. Secondary objectives were to evaluate Tdap vaccination coverage, to assess predictive factors associated with anti-PT IgG, and to estimate the decay of anti-PT IgG and time to Tdap vaccination. METHODS: Observational cross-sectional serological study in 352 HCPs who worked at São Paulo Hospital - Federal University of São Paulo (UNIFESP) in 2020, approved by UNIFESP Ethics Committee. Data collected included sociodemographics, knowledge about Tdap, and vaccination status. Anti-PT IgG were quantified by ELISA: <10 IU/mL seronegative and ≥ 10-1000 IU/mL seropositive. Titers ≥ 10-50 IU/mL were classified low positivity, indicating no recent B. pertussis infection or Tdap vaccination; >50 IU/mL high positivity, indicating recent B. pertussis infection or Tdap vaccination, and > 100 IU/mL as acute B. pertussis infection or Tdap vaccination in the previous year. Comparisons were done by Chi-square test, multivariable logistic regression, and Pearsons correlation, at 5% p-level. RESULTS: 331/352 HCPs were not aware the Brazilian National Immunization Program recommends Tdap for all HCPs and pregnant women. 68/339 HCPs received Tdap (mean 3.1 ± 2.0 years). 55/352 were seronegative for pertussis, all unvaccinated. 56/271 with no history of Tdap vaccination had high positivity. The probability of anti-PT IgG > 50 IU/mL was 11.5 times higher in Tdap vaccinated HCPs than in non-vaccinated (p < 0.001). There was a weak but significant correlation between anti-PT IgG and interval of Tdap vaccination (r = 0.404; p = 0.001). Anti-PT IgG dropped 5 IU/mL/year (p = 0.001). CONCLUSION: Better education of HCPs on needs and benefits of Tdap vaccination is critical. Goals must be to improve HCPs vaccination coverage.

A randomized, double-blind, non-inferiority trial comparing the immunogenicity and safety of two seasonal inactivated influenza vaccines in adults.

BACKGROUND: To enhance the production and availability of influenza vaccines in different regions of the world is paramount to mitigate the global burden of this disease. Instituto Butantan developed and manufactured an embryonated egg-based inactivated split-virion trivalent seasonal influenza vaccine as part of a technology transfer partnership with Sanofi Pasteur. METHODS: This is a phase IV, randomized, double-blind, active-controlled, multicenter clinical trial including adults 18-60 and > 60 years recruited during the 2019 southern hemisphere influenza season. Subjects were randomized 1:1 to receive either the Sanofi Pasteur Trivalent Seasonal Influenza Vaccine (SP-TIV) or Instituto Butantan Trivalent Seasonal Influenza Vaccine (IB-TIV). Hemagglutinin inhibition antibody titers were assessed pre-vaccination and 21 days post-vaccination. RESULTS: 624 participants were randomized and vaccinated. In both intention-to-treat and per-protocol analysis, non-inferiority of the SP-TIV versus IB-TIV was demonstrated for the three influenza strains. In the per-protocol analysis, the SP-GMT/IB-GMT ratios for H1N1, H3N2, and B were 0.9 (95%CI, 0.7-1.1), 1.2 (95%CI, 1.0-1.4), and 1.1 (95%CI, 0.9-1.3), respectively. Across vaccination groups, the most common adverse reactions (AR) were limited to the injection-site, including pain and tenderness. The majority of the ARs were graded 1 and/or 2 and lasted less than one day. No serious adverse reaction was observed. CONCLUSION: This study demonstrated the non-inferiority of the immunogenicity of a single-dose of Instituto Butantan versus a single dose of the Sanofi Pasteur Seasonal Trivalent Influenza Vaccine in adults. Both vaccines were well tolerated and presented similar safety profiles.

An exploratory analysis of the response to ChAdOx1 nCoV-19 (AZD1222) vaccine in males and females.

BACKGROUND: There are known differences in vaccine reactogenicity and immunogenicity by sex. Females have been shown to report greater reactogenicity and generate higher humoral and cellular immune responses than males following vaccination with several different vaccines. Whether this is also the case for COVID-19 vaccines is currently unknown, as COVID-19 vaccine study data disaggregated by sex are not routinely reported. Therefore, we have assessed the influence of sex on reactogenicity, immunogenicity and efficacy of COVID-19 vaccine ChAdOx1 nCoV-19. METHODS: Vaccine efficacy was assessed in 15169 volunteers enrolled into single-blind randomised controlled trials of ChAdOx1 nCoV-19 in Brazil and the UK, with the primary endpoint defined as nucleic acid amplification test (NAAT)-positive symptomatic SARS-CoV-2 infection. All participants were electronically randomised to receive two standard doses of vaccine or the control product. Logistic regression models were fitted to explore the effect of age and sex on reactogenicity, and linear models fitted to log-transformed values for immunogenicity data. Reactogenicity data were taken from self-reported diaries of 788 trial participants. Pseudovirus neutralisation assay data were available from 748 participants and anti-SARS-CoV-2 spike IgG assay data from 1543 participants. FINDINGS: 7619 participants received ChAdOx1 nCoV-19 and 7550 received the control. Vaccine efficacy in participants after two doses of ChAdOx1 nCoV-19 (4243 females and 3376 males) was 66.1% (95% CI 55.9-73.9%) in males and 59.9% (95% CI 49.8-67.9%) in females; with no evidence of a difference in efficacy between the sexes (vaccine by sex interaction term P=0.3359). A small, statistically significant difference in anti-spike IgG was observed (adjusted GMR 1.14; 95% CI 1.04-1.26), with higher titres in females than males, but there were no statistically significant differences in other immunological endpoints. Whilst the majority of individuals reported at least one systemic reaction following a first dose of ChAdOx1 nCoV-19, females were twice as likely as males to report any systemic reaction after a first dose (OR 1.95; 95% CI 1.37-2.77). Measured fever of 38°C or above was reported in 5% of females and 1% of males following first doses. Headache and fatigue were the most commonly reported reactions in both sexes. INTERPRETATION: Our results show that there is no evidence of difference in efficacy of the COVID-19 vaccine ChAdOx1 nCoV-19 in males and females. Greater reactogenicity in females was not associated with any difference in vaccine efficacy. FUNDING: Studies were registered with ISRCTN 90906759 (COV002) and ISRCTN 89951424 (COV003) and follow-up is ongoing. Funding was received from the UK Research and Innovation, Engineering and Physical Sciences Research Council, National Institute for Health Research, Coalition for Epidemic Preparedness Innovations, National Institute for Health Research Oxford Biomedical Research Centre, Chinese Academy of Medical Sciences Innovation Fund for Medical Science, Thames Valley and South Midlands NIHR Clinical Research Network, the Lemann Foundation, Rede D'Or, the Brava and Telles Foundation, the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior, Brazil, and AstraZeneca.

Capsular genotype distribution of Group B Streptococcus colonization among at-risk pregnant women in Sao Paulo, Brazil.

BACKGROUND: Vaccines in development against Group B Streptococcus (GBS) should contain the most prevalent capsular genotypes screened in the target population. In low- and middle-income countries epidemiological data on GBS carriage among pregnant women, a prerequisite condition for GBS neonatal sepsis, is needed to inform vaccine strategies. OBJECTIVE: To investigate the prevalence of different GBS capsular genotypes that colonizes at-risk pregnant women in a private maternity hospital in São Paulo, Brazil. METHODS: GBS strains isolated in routine maternity procedures from at-risk pregnant women from 2014 to 2018 were confirmed by mass spectrometry (MALDI-TOF) with subsequent DNA extraction for identification of capsular genotype through polymerase chain reaction (PCR). Demographic and gestational data were analyzed. RESULTS: A total of 820 Todd-Hewitt broths positive for GBS were selected for streptococcal growth. Recovery and confirmation of GBS by MALDI-TOF were possible in 352. Strains were processed for determination of capsular genotype by PCR. From the total of 352 GBS isolates, 125 strains (35.5%) were genotyped as Ia; 23 (6.5%) as Ib; 41 (11.6%) as II; 36 (10.2%) as III; 4 (1.1%) as IV; 120 (34.1%) as V and 1 strain (0.3%) as VIII. Two isolates (0.7%) were not genotyped by used methodology. No statistically significant correlation between gestational risk factors, demographic data and distribution of capsular genotypes were found. CONCLUSIONS: GBS capsular genotypes Ia, Ib, II, III, and V were the most prevalent isolates colonizing at risk pregnant women in the present study. The inclusion of capsular genotypes Ia and V in the composition of future vaccines would cover 69.6% of capsular genotypes in the studied population. No statistically significant differences were observed between capsular genotype and gestational and demographic data and risk factors.

Efficacy of ChAdOx1 nCoV-19 (AZD1222) vaccine against SARS-CoV-2 lineages circulating in Brazil.

Several COVID-19 vaccines have shown good efficacy in clinical trials, but there remains uncertainty about the efficacy of vaccines against different variants. Here, we investigate the efficacy of ChAdOx1 nCoV-19 (AZD1222) against symptomatic COVID-19 in a post-hoc exploratory analysis of a Phase 3 randomised trial in Brazil (trial registration ISRCTN89951424). Nose and throat swabs were tested by PCR in symptomatic participants. Sequencing and genotyping of swabs were performed to determine the lineages of SARS-CoV-2 circulating during the study. Protection against any symptomatic COVID-19 caused by the Zeta (P.2) variant was assessed in 153 cases with vaccine efficacy (VE) of 69% (95% CI 55, 78). 49 cases of B.1.1.28 occurred and VE was 73% (46, 86). The Gamma (P.1) variant arose later in the trial and fewer cases (N = 18) were available for analysis. VE was 64% (-2, 87). ChAdOx1 nCoV-19 provided 95% protection (95% CI 61%, 99%) against hospitalisation due to COVID-19. In summary, we report that ChAdOx1 nCoV-19 protects against emerging variants in Brazil despite the presence of the spike protein mutation E484K.

Active pharmacovigilance of the seasonal trivalent influenza vaccine produced by Instituto Butantan: A prospective cohort study of five target groups.

INTRODUCTION: Active pharmacovigilance studies are pivotal to better characterize vaccine safety. METHODS: These are multicenter prospective cohort studies to evaluate the safety of the 2017 and 2018 seasonal trivalent influenza vaccines (TIVs) manufactured by Instituto Butantan, by means of active pharmacovigilance practices. Elderly, children, healthcare workers, pregnant women, and women in the puerperium period were invited to participate in the study during the 2017 and 2018 Brazilian national seasonal influenza vaccination campaigns. Following immunization, participants were observed for 30 minutes and they received a participant card to register adverse events information. All safety information registered were checked at a clinical site visit 14 days after immunization and by a telephone contact 42 days after immunization for unsolicited Adverse Events (AE) and Guillain-Barré Syndrome (GBS). RESULTS: A total of 942 volunteers participated in the two studies: 305 elderly, 109 children, 108 pregnant women, 32 women in the postpartum period, and 388 health workers. Overall, the median number of AR per participant ranged from 1 to 4. The lowest median number of AR per participant was observed among healthcare workers (1 AR per participant) and the highest among pregnant women (4 AR per participant). Overall, local pain (46.6%) was the most frequent solicited local AR. The most frequent systemic ARs were: headache (22.5%) followed by fatigue (16.0%), and malaise (11.0%). The majority of solicited ARs (96%) were mild, Grades 1 or 2), only 3% were Grade 3, and 1% was Grade 4. No serious AEs, including Guillain-Barré Syndrome, were reported up to 42 days postvaccination. CONCLUSION: The results from the two studies confirmed that the 2017 and 2018 seasonal trivalent influenza vaccines produced by Instituto Butantan were safe and that active pharmacovigilance studies should be considered, when it is feasible, as an important initiative to monitor vaccine safety in the post-marketing period.

Humoral and cellular immune responses to measles and tetanus: the importance of elapsed time since last exposure and the nature of the antigen.

OBJECTIVE: This study aims to assess the cellular and humoral immune response pre- and post-vaccine rechallenge in healthy adults with previous exposure to measles (virus or vaccine) and different time intervals since last tetanus vaccine. METHODS: Humoral immunity was tested by ELISA, and cellular immunity was tested by intracellular interferon gamma detection after in vitro stimulation with antigens. RESULTS: While cellular immunity was comparable among vaccinated individuals and those who had measles, higher antibody levels were found in those who had the disease in the past. Both antibodies and CD4(+) T cell tetanus immune responses depended on elapsed time since last immunization. Following a vaccine booster, an increase in cellular immunity and antibodies was observed to both tetanus and measles. Measles humoral response was much more intense among individuals previously exposed to a wild virus. CONCLUSIONS: In an era when natural boosters are less frequent, an immune surveillance might be necessary to investigate waning immunity as occurs for tetanus.

Night shift work and immune response to the meningococcal conjugate vaccine in healthy workers: a proof of concept study.

BACKGROUND: It is well-established that sleep regulates immune functions. Immunological functions are dependent on circadian rhythms and regular sleep as both have an impact on the magnitude of immune responses following antigenic challenge (eg, in vaccination). Here we investigated whether nocturnal shift work can influence post-vaccination response. METHODS: Thirty-four healthy workers (23 females) working either nocturnal or diurnal shifts (17 in each group) received the meningococcal C meningitis vaccine. Sleep was recorded polysomnographically (PSG) and with actigraphy. Humoral and cellular responses were assessed after vaccination. RESULTS: Night workers showed decreased N3 stage and REM sleep duration, increased inflammatory mediators (TNF-α and IL-6 levels), and a weak specific humoral response to vaccination associated with reduced CD4 T lymphocytes, reduced plasmacytoid dendritic cells, reduced prolactin levels, increased TReg and increased IL-10 levels. In addition, the decrease in total sleep time and circadian rhythm alterations were associated with a reduced humoral response post-vaccination. CONCLUSIONS: Our findings provide novel evidence concerning immune alterations of shift work on workers' health based on real-life circumstances. In association with circadian components, sufficient sleep time and rhythm synchronization were important for the development of the Ag-specific immune response, suggesting that the humoral response to vaccination may be impaired in individuals with chronic sleep restriction and circadian misalignment.