Genomic Surveillance of Yellow Fever Virus Epizootic in São Paulo, Brazil, 2016 - 2018.

São Paulo, a densely inhabited state in southeast Brazil that contains the fourth most populated city in the world, recently experienced its largest yellow fever virus (YFV) outbreak in decades. YFV does not normally circulate extensively in São Paulo, so most people were unvaccinated when the outbreak began. Surveillance in non-human primates (NHPs) is important for determining the magnitude and geographic extent of an epizootic, thereby helping to evaluate the risk of YFV spillover to humans. Data from infected NHPs can give more accurate insights into YFV spread than when using data from human cases alone. To contextualise human cases, identify epizootic foci and uncover the rate and direction of YFV spread in São Paulo, we generated and analysed virus genomic data and epizootic case data from NHPs in São Paulo. We report the occurrence of three spatiotemporally distinct phases of the outbreak in São Paulo prior to February 2018. We generated 51 new virus genomes from YFV positive cases identified in 23 different municipalities in São Paulo, mostly sampled from NHPs between October 2016 and January 2018. Although we observe substantial heterogeneity in lineage dispersal velocities between phylogenetic branches, continuous phylogeographic analyses of generated YFV genomes suggest that YFV lineages spread in São Paulo at a mean rate of approximately 1km per day during all phases of the outbreak. Viral lineages from the first epizootic phase in northern São Paulo subsequently dispersed towards the south of the state to cause the second and third epizootic phases there. This alters our understanding of how YFV was introduced into the densely populated south of São Paulo state. Our results shed light on the sylvatic transmission of YFV in highly fragmented forested regions in São Paulo state and highlight the importance of continued surveillance of zoonotic pathogens in sentinel species.

Diversity of enteric and non-enteric human adenovirus strains in Brazil, 2006-2011.

During 2006-2011, 5035 fecal samples were tested by PCR for human adenovirus (HAdV) and sequenced. HAdV was detected in 198 cases (3.9%), with the highest rate in children ≤ 5 years. Enteric HAdVs were the most prevalent genotypes (78%; 146/187): HAdV-F41 (63.6%; 119/187), HAdV-F40 (12.3%; 23/187), HAdV-A12 (1.6%; 3/187) and HAdV-A31 (0.5%; 1/187). Non-enteric HAdVs were detected in 22% (41/187): HAdV-C1 (8.0%; 15/187), HAdV-C2 (6.9%; 13/187), HAdV-C5 (4.3%; 8/187), HAdV-D8 (1.3%; 2/187), HAdV-B21 (0.5%; 1/187), HAdV-B3 (0.5%; 1/187) and HAdV-C6 (0.5%; 1/187). This 6-year retrospective study points out a high diversity of HAdV types circulating in Brazil and highlights the need to carry out molecular epidemiological studies of HAdV among patients with acute diarrheal infection on a regular basis.

Distribution of species enterovirus B in patients with central nervous system infections in São Paulo State, Brazil.

Enteroviruses (EV) are most common cause of central nervous system (CNS) infection, mainly aseptic meningitis. In Brazil, data available concerning the distribution of EV types are scarce. The aim of this study was to describe of types EV in patients with infection of the CNS in São Paulo State. This retrospective study was conducted in clinical samples collected from patients with infections of the CNS from 2004 to 2014. We investigated the presence of EV by virus isolation in cell culture. The samples that showed cytopathic effect in the cell culture were submitted by indirect immunofluorescence assay, reverse transcription polymerase chain reaction and VP1 partial sequencing to identification of EV isolated. A total of 176 EV isolated in cell culture was detected and typed in 14.5% (n = 176/1215) of clinical samples analyzed; corresponding to 71.0% of AM, and 19.3% of encephalitis and meningoencephalitis. Echoviruses (E) were isolated most frequently, with 155 strains (88.1%), Coxsackievirus B (CV-B), with 20 cases (11.4%), CV-A, with 01 case (0.6%). E-6 was the most commonly identified followed in decreasing order by E-30; E-18; CV-B5; E-4; E-11; CV-B2 and E-9; E-7; CV-A9, CV-B1, CV-B3, CV-B4, E-13, E-14, and E-21. EV detected were classified as belonging to the species enterovirus B. EV were detected in all the period of the year with the highest rate in the spring and summer months. Data obtained in this study contribute to the knowledge about EV circulation implicated in CNS infections over a 11-year period in São Paulo State, Brazil.

Spread of the emerging equine-like G3P[8] DS-1-like genetic backbone rotavirus strain in Brazil and identification of potential genetic variants.

In 2013, the equine-like G3P[8] DS-1-like rotavirus (RVA) strain emerged worldwide. In 2016, this strain was reported in northern Brazil. The aims of the study were to conduct a retrospective genetic investigation to identify the possible entry of these atypical strains in Brazil and to describe their distribution across a representative area of the country. From 2013 to 2017, a total of 4226 faecal samples were screened for RVA by ELISA, PAGE, RT-PCR and sequencing. G3P[8] represented 20.9 % (167/800) of all RVA-positive samples, further subdivided as equine-like G3P[8], DS-1-like (11.0 %; 88/800) and Wa-like G3P[8] (9.9 %; 79/800). Six equine-like G3P[8] DS-1-like samples were selected for whole-genome investigation, confirming the backbone I2-R2-C2-M2-A2-N2-T2-E2-H2. During 2013-2014, Wa-like G3P[8] was predominant and no equine-like G3P[8] DS-1-like was detected. Equine-like G3P[8] DS-1-like was first identified in Paraná in March/2015, suggesting that the strain entered Brazil through the Southern region. Equine-like G3P[8] rapidly spread across the area under surveillance and displayed a marked potential to replace Wa-like G3P[8] strains. Brazilian equine-like G3P[8] DS-1-like strains clustered with contemporary equine-like G3P[8] DS-1-like detected worldwide, but exhibited a distinct NSP2 genotype (N2) compared to the previously reported Amazon equine-like G3P[8] DS-1-like strain (N1). Two distinct NSP4 E2 genotype lineages were also identified. Taken together, these data suggest that different variants of equine-like G3P[8] DS-1-like strains might have been introduced into the country at distinct time points, and co-circulated in the period 2015-2017. The global emergence of equine-like G3P[8] DS-1-like strains, predominantly in countries using the Rotarix vaccine, raises the question of whether vaccines may be inducing selective pressures on zoonotic strains.

Potent Plasmablast-Derived Antibodies Elicited by the National Institutes of Health Dengue Vaccine.

Exposure to dengue virus (DENV) is thought to elicit lifelong immunity, mediated by DENV-neutralizing antibodies (nAbs). However, Abs generated by primary infections confer serotype-specific protection, and immunity against other serotypes develops only after subsequent infections. Accordingly, the induction of these nAb responses acquired after serial DENV infections has been a long-sought-after goal for vaccination. Nonetheless, it is still unclear if tetravalent vaccines can elicit or recall nAbs. In this study, we have characterized the responses from a volunteer who had been previously exposed to DENV and was immunized with the live attenuated tetravalent vaccine Butantan-DV, developed by the NIH and Butantan Institute. Eleven days after vaccination, we observed an ∼70-fold expansion of the plasmablast population. We generated 21 monoclonal Abs (MAbs) from singly sorted plasmablasts. These MAbs were the result of clonal expansions and had significant levels of somatic hypermutation (SHM). Nineteen MAbs (90.5%) neutralized at least one DENV serotype at concentrations of 1 µg/ml or less; 6 of the 21 MAbs neutralized three or more serotypes. Despite the tetravalent composition of the vaccine, we observed a neutralization bias in the induced repertoire: DENV3 was targeted by 18 of the 19 neutralizing MAbs (nMAbs). Furthermore, the P3D05 nMAb neutralized DENV3 with extraordinary potency (concentration to achieve half-maximal neutralization [Neut50] = 0.03 µg/ml). Thus, the Butantan-DV vaccine engendered a mature, antigen-selected B cell repertoire. Our results suggest that preexisting responses elicited by a previous DENV3 infection were recalled by immunization.IMPORTANCE The dengue epidemic presents a global public health challenge that causes widespread economic burden and remains largely unchecked by existing control strategies. Successful control of the dengue epidemic will require effective prophylactic and therapeutic interventions. Several vaccine clinical efficacy trials are approaching completion, and the chances that one or more live attenuated tetravalent vaccines (LATVs) will be introduced worldwide is higher than ever. While it is widely accepted that dengue virus (DENV)-neutralizing antibody (nAb) titers are associated with protection, the Ab repertoire induced by LATVs remain uncharacterized. Here, we describe the isolation of potent (Neut50 < 0.1 µg/ml) nAbs from a DENV-seropositive volunteer immunized with the tetravalent vaccine Butantan-DV, which is currently in phase III trials.

Pandemic non-adjuvanted influenza A H1N1 vaccine in a cohort of patients with systemic sclerosis.

Objective: To assess the possible effect of therapy, disease subtype and severity on H1N1 immunogenicity in patients with SSc. Methods: Ninety-two patients and 92 age- and gender-matched healthy controls received adjuvant-free influenza A/California/7/2009 (pH1N1) vaccine. Blood samples were collected immediately before and 3 weeks after vaccination to evaluate antibody responses to the H1N1 virus. Efficacy was assessed by seroprotection (SP) and seroconversion (SC) rates and the factor increase in geometric mean antibody titre. Participants received a 21-day symptom diary card and were instructed to report local and systemic adverse events. Results: SSc patients were predominantly females (91%) and 61% had limited SSc, 12% had severe skin involvement and 57.6% were on immunosuppressive (IS) therapy. SSc patients and controls presented comparable overall SP (P = 0.20) and SC (P = 0.61) rates. Further evaluation of the possible effect of disease and therapy revealed similar rates of SP and SC in patients with dcSSc vs lcSSc (SP P = 0.62 and SC P = 0.66), severe vs mild/moderate skin involvement (SP P = 1 and SC P = 0.45) and with vs without IS (SP P = 0.26 and SC P = 0.10). The frequency of mild local and minor systemic reactions was similar in patients with dcSSC vs lcSSc (P = 0.70 vs 0.32) and in those with and without severe skin involvement (P = 0.59 vs 0.28). Conclusion: The non-adjuvanted influenza H1N1 virus vaccine proved to be safe and effective, independent of SSc clinical subtype, disease severity or therapy. These latter factors do not seem to contribute to mild adverse events observed in SSc. Our data support the annual influenza vaccination recommendation for these patients. Trial registration: ClinicalTrials.gov (http://clinicaltrials.gov), NCT01151644.

Detection and genetic characterization of classic human astroviruses in Brazil, 2010-2012.

The aims of this study were to monitor human astrovirus (HAstV) infections in patients presenting with acute gastroenteritis in Brazil and to determine the HAstV genotypes of these viruses. From May 2010 to July 2012, a total of 140 samples that were negative for both rotaviruses and noroviruses were randomly selected and tested for the presence of HAstV using an RT-PCR assay specific for the ORF2 region. Viral genotypes were identified and genetic diversity was investigated by sequencing. HAstV infection was detected in 2.9% of samples (4/140). The viruses in three samples were shown by phylogenetic analysis to belong to HAstV-4 lineage "c", clustering together with strains detected in Europe and the Middle East. The virus in one sample was genotyped as HAstV-1 lineage "a", clustering with strains from Uruguay, Brazil and Russia. Our findings provide further evidence for a global distribution of HAstV-1a and suggest a possible emergent importance of the HAstV-4c lineage in this country. The present study does not suggest that HAstVs currently have a major epidemiological impact, even after the introduction of a rotavirus vaccine in 2006.

Outbreak of G2P[4] rotavirus gastroenteritis in a retirement community, Brazil, 2015: An important public health risk?

The present study described a group A rotavirus (RVA) outbreak in an age-care facility in Brazil, using epidemiologic and molecular diagnostic methods. A descriptive clinical, epidemiological and environmental investigation was conducted. Stool samples were collected and screened for RVA, Norovirus (NoV), Enteric Adenovirus 40/41 (AdV 40/41) and Astrovirus (AstV) using ELISA, RT-PCR, qRT-PCR, electron microscopy and sequencing methods. Outbreak occurred during 26th-29th October, 2015; 28 individuals affected (22 residents; 6 staff). The attack rate was 25.9% and 8.5% among residents (median-age: 85.5 years) and staff (median-age: 28 years), respectively. Female staff was identified as the index case. RVA G2P[4] genotype was detected in 87.5% (7/8). Genetic analysis demonstrated that the outbreak involved one single strain, suggesting a common-source infection. RVA should be considered during outbreaks investigations in residential facilities, and raise the question if the current licensed RVA vaccines for children could also be helpful for the elderly.

Acute hemorrhagic conjunctivitis epidemic in São Paulo State, Brazil, 2011.

Acute hemorrhagic conjunctivitis (AHC) infection is highly contagious and can lead to explosive epidemics. In early February 2011, the Center for Epidemiologic Surveillance of the State of São Paulo Health Secretariat (SES-SP) in Brazil received reports of conjunctivitis outbreaks from rural areas of the state that subsequently spread statewide. This report describes that AHC epidemic and its etiologic agent. Data from the Ministry of Health Information System for Notifiable Diseases (SinanNet) and the SES-SP epidemiologic surveillance system for conjunctivitis, developed to detect outbreaks, confirm the etiologic agent, and carry out control measures, were analyzed. Eye (conjunctival swab) samples were taken from patients with clinical presentation of viral conjunctivitis to perform viral laboratory diagnosis. A total of 1 067 981 conjunctivitis cases were reported to the surveillance system for 2011; there was an increase in the number of cases in epidemiologic weeks 6-26 (summer season) versus previous years. Most cases occurred in the metropolitan region of Greater São Paulo. Of 93 collected samples, 57 tested positive for coxsackievirus-A24 (CV-A24), based on virus isolation in tissue-culture cell lines, reverse transcription polymerase chain reaction (RT-PCR), and enterovirus sequencing of RT-PCR. The data analysis showed that the fast-spreading etiologic agent of the AHC epidemic that occurred in the summer of 2011 was CV-A24. The AHC epidemic was due to an enterovirus that occurred sporadically, spread rapidly and with great magnitude, and had substantial socioeconomic impact due to the high level of absenteeism at work and school.

Rotavirus genotypes and the indigenous children of Brazilian midwest in the vaccine era, 2008-2012: Footprints of animal genome.

World group A rotavirus (RVA) surveillance data provides useful estimates of the disease burden, however, indigenous population might require special consideration. The aim of this study was to describe the results of G- and P-types from Brazilian native children ≤ 3 years. Furthermore, selected strains have been analyzed for the VP7, VP6, VP4, and NSP4 encoding genes in order to gain insight into genetic variability of Brazilian strains. A total of 149 samples, collected during 2008-2012, were tested for RVA using ELISA and PAGE, following by RT-PCR and sequencing. RVA infection was detected in 8.7% of samples (13/149). Genotype G2P[4] was detected in 2008 and 2010, G8P[6] in 2009, and G3P[8] in 2011. The phylogenetic analysis of the VP7 and VP4 genes grouped the Brazilian G2P[4] and G3P[8] strains within the lineages currently circulating in humans worldwide. However, the phylogenetic analysis of the VP6 and NSP4 from the Brazilian G2P[4] strains, and the VP7 and NSP4 from the Brazilian G3P[8] strains suggest a distant common ancestor with different animal strains (bovine, caprine, and porcine). The epidemiological and genetic information obtained in the present study is expected to provide an updated understanding of RVA genotypes circulating in the native infant population, and to formulate policies for the use of RVA vaccines in indigenous Brazilian people. Moreover, these results highlight the great diversity of human RVA strains circulating in Brazil, and an in-depth surveillance of human and animal RVA will lead to a better understanding of the complex dynamics of RVA evolution.

G8P[6] rotaviruses isolated from Amerindian children in Mato Grosso do Sul, Brazil, during 2009: close relationship of the G and P genes with those of bovine and bat strains.

During the 2009 national group A rotavirus (RVA) surveillance, five unusual strains of the human G8P[6] genotype were detected in Brazilian indian children with acute gastroenteritis. The aim of this study was to carry out sequence analysis of the two outer capsid proteins (VP4 and VP7) and the inner capsid protein (VP6) of the G8P[6] strains detected in order to provide further information on the genetic relationship between human and animal RVA. A total of 68 stool samples, collected in Mato Grosso do Sul during 2009, were tested for RVA using ELISA, following by reverse transcriptase-PCR and sequencing. RVA infection was detected in 7.3% of samples (5/68). The IAL-RN376 G8 sequence shares a clade with bovine and human strains, displaying highest nucleotide identity to African human strains DRC86 and DRC88, followed by African bovine strain NGRBg8. IAL-RN376 and IAL-RN377 P[6] sequences showed highest identity to human strain R330 from Ireland, and a close genetic relationship to African fruit bat RVA strain KE4852/07. Strains IAL-RN376 and IAL-RN377 display genogroup I VP6 specificity and the I2 genotype, and share high nucleotide identities with human strains B1711, 272-BF and 06-242, and moderate identities with bovine (RUBV81, 86 and KJ9-1) and porcine (HP140) strains. This study suggested that a reassortment between bovine and bat RVA strains could have occurred in animal host(s) preceding the transmission to humans. In the indigenous population, zoonotic transmission is probably fairly frequent as the inhabitants live in close contact with animals under conditions of poor hygiene.

Rubella virus genotype 1G and echovirus 9 as etiologic agents of exanthematous diseases in Brazil: insights from phylogenetic analysis.

The aim of the present study was to identify the rubella virus (RV) and enterovirus (EV) genotypes detected during the Epidemiological Surveillance on Exanthematic Febrile Diseases (VIGIFEX) study and to perform phylogenetic analysis. Ten RV- and four EV-positive oropharyngeal samples isolated from cell culture were subjected to RT-PCR and sequencing. Genotype 1G and echovirus 9 (E-9) was identified in RV- and EV-positive samples, respectively. The RV 1G genotype has been persisting in Brazil since 2000-2001. No evidence of E-9 being involved in exanthematic illness in Brazil has been reported previously. Differential laboratory diagnosis is essential for management of rash and fever disease.

A pre-vaccination immune metabolic interplay determines the protective antibody response to a dengue virus vaccine.

Protective immunity to dengue virus (DENV) requires antibody response to all four serotypes. Systems vaccinology identifies a multi-OMICs pre-vaccination signature and mechanisms predictive of broad antibody responses after immunization with a tetravalent live attenuated DENV vaccine candidate (Butantan-DV/TV003). Anti-inflammatory pathways, including TGF-ß signaling expressed by CD68low monocytes, and the metabolites phosphatidylcholine (PC) and phosphatidylethanolamine (PE) positively correlate with broadly neutralizing antibody responses against DENV. In contrast, expression of pro-inflammatory pathways and cytokines (IFN and IL-1) in CD68hi monocytes and primary and secondary bile acids negatively correlates with broad DENV-specific antibody responses. Induction of TGF-ß and IFNs is done respectively by PC/PE and bile acids in CD68low and CD68hi monocytes. The inhibition of viral sensing by PC/PE-induced TGF-ß is confirmed in vitro. Our studies show that the balance between metabolites and the pro- or anti-inflammatory state of innate immune cells drives broad and protective B cell response to a live attenuated dengue vaccine.

Serological evidence of arenavirus circulation in wild rodents from central-west, southeast, and south regions of Brazil, 2002-2006.

Viral hemorrhagic fevers caused by arenaviruses are severe zoonotic diseases. In reservoirs, the presence of antibodies may indicate viral circulation in a population of a specific region, and these data can be used as an indicator for further investigations by molecular techniques. The present study aimed to detect the presence of arenavirus antibodies in wild rodents captured from 1998 to 2008 during epidemiological surveillance activities. A retrospective analysis of 2243 wild rodent blood samples using a broad cross-reactive in-house developed enzyme-linked immunosorbent assay (ELISA) revealed a 0.44% (10/2243) positive rate in wild rodents, which included Necromys lasiurus (6/1012), Calomys callosus (2/94), and Akodon sp. (2/273) species. These rodents were captured between 2002 to 2006 in Campo Alegre de Goiás/GO, Bodoquena/MS, Nuporanga/SP, and Mogi das Cruzes/SP. Our findings suggest the sylvatic circulation of arenavirus among wild rodents in the southeast region of Brazil. However, future virological and molecular studies are necessary to confirm the viral presence in these regions.

Pegivirus Detection in Cerebrospinal Fluid from Patients with Central Nervous System Infections of Unknown Etiology in Brazil by Viral Metagenomics.

Metagenomic next-generation sequencing (mNGS) methodology serves as an excellent supplement in cases where diagnosis is challenging to establish through conventional laboratory tests, and its usage is increasingly prevalent. Examining the causes of infectious diseases in the central nervous system (CNS) is vital for understanding their spread, managing outbreaks, and effective patient care. In a study conducted in the state of São Paulo, Brazil, cerebrospinal fluid (CSF) samples from 500 patients with CNS diseases of indeterminate etiology, collected between 2017 and 2021, were analyzed. Employing a mNGS approach, we obtained the complete coding sequence of Pegivirus hominis (HPgV) genotype 2 in a sample from a patient with encephalitis (named IAL-425/BRA/SP/2019); no other pathogen was detected. Subsequently, to determine the extent of this virus's presence, both polymerase chain reaction (PCR) and/or real-time PCR assays were utilized on the entire collection. The presence of the virus was identified in 4.0% of the samples analyzed. This research constitutes the first report of HPgV detection in CSF samples in South America. Analysis of the IAL-425 genome (9107 nt) revealed a 90% nucleotide identity with HPgV strains from various countries. Evolutionary analyses suggest that HPgV is both endemic and extensively distributed. The direct involvement of HPgV in CNS infections in these patients remains uncertain.

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.

Plasmablast Expansion Following the Tetravalent, Live-Attenuated Dengue Vaccine Butantan-DV in DENV-Naïve and DENV-Exposed Individuals in a Brazilian Cohort.

An effective vaccine against the dengue virus (DENV) should induce a balanced, long-lasting antibody (Ab) response against all four viral serotypes. The burst of plasmablasts in the peripheral blood after vaccination may reflect enriched vaccine-specific Ab secreting cells. Here we characterize the acute plasmablast responses from naïve and DENV-exposed individuals following immunization with the live attenuated tetravalent (LAT) Butantan DENV vaccine (Butantan-DV). The frequency of circulating plasmablasts was determined by flow cytometric analysis of fresh whole blood specimens collected from 40 participants enrolled in the Phase II Butantan-DV clinical trial (NCT01696422) before and after (days 6, 12, 15 and 22) vaccination. We observed a peak in the number of circulating plasmablast at day 15 after vaccination in both the DENV naïve and the DENV-exposed vaccinees. DENV-exposed vaccinees experienced a significantly higher plasmablast expansion. In the DENV-naïve vaccinees, plasmablasts persisted for approximately three weeks longer than among DENV-exposed volunteers. Our findings indicate that the Butantan-DV can induce plasmablast responses in both DENV-naïve and DENV-exposed individuals and demonstrate the influence of pre-existing DENV immunity on Butantan DV-induced B-cell responses.

An Open-label Randomized Controlled Parallel-group Pilot Study Comparing the Immunogenicity of a Standard-, Double-, and Booster-dose Regimens of the 2014 Seasonal Trivalent Inactivated Influenza Vaccine in Kidney Transplant Recipients.

BACKGROUND: Immunogenicity of influenza vaccine in transplant recipients is suboptimal and alternative vaccination regimens are necessary. METHODS: We compared the immunogenicity of a standard-dose trivalent inactivated influenza vaccination (SDTIIV), double-dose trivalent inactivated influenza vaccination (DDTIIV), and booster-dose trivalent inactivated influenza vaccination (BDTIIV) of the 2014 seasonal trivalent inactivated influenza vaccine in kidney transplant recipients. We randomized 176 participants to SDTIIV (59), DDTIIV (59), and BDTIIV regimens (58). Antibody titers were determined by hemagglutination inhibition at enrollment and 21 d postvaccination. Seroprotection rates (SPRs), seroconversion rates (SCRs), and geometric mean ratios (GMRs) were analyzed separately for participants with low (<1:40) and high (≥1:40) prevaccination antibody titers. RESULTS: Vaccination was confirmed for 172 participants. Immunogenicity analysis was done for 149 participants who provided postvaccination blood samples. In the subgroup with high prevaccination antibody titers, all vaccination regimens induced SPR > 70% to all antigens, but SCR and GMR were below the recommendations. In the subgroup with low prevaccination antibody titers, DDTIIV and BDTIIV regimens induced adequate SCR > 40% and GMR > 2.5 for all antigens, whereas SDTIIV achieved the same outcomes only for influenza B. SPRs were >70% only after DDTIIV (A/H1N1-77.8%) and BDTIIV (A/H3N2-77.8%). BDTIIV regimen independently increased seroprotection to A/H1N1 (PR = 2.58; P = 0.021) and A/H3N2 (PR = 2.21; P = 0.004), whereas DDTIIV independently increased seroprotection to A/H1N1 (PR = 2.59; P = 0.021). CONCLUSIONS: Our results suggest that DDTIIV and BDTIIV regimens are more immunogenic than SDTIIV, indicating the need for head-to-head multicenter clinical trials to further evaluate their efficacy.

Dose-sparing effect of two adjuvant formulations with a pandemic influenza A/H7N9 vaccine: A randomized, double-blind, placebo-controlled, phase 1 clinical trial.

The emergence of potentially pandemic viruses has resulted in preparedness efforts to develop candidate vaccines and adjuvant formulations. We evaluated the dose-sparing effect and safety of two distinct squalene-based oil-in-water adjuvant emulsion formulations (IB160 and SE) with influenza A/H7N9 antigen. This phase I, randomized, double-blind, placebo-controlled, dose-finding trial (NCT03330899), enrolled 432 healthy volunteers aged 18 to 59. Participants were randomly allocated to 8 groups: 1A) IB160 + 15µg H7N9, 1B) IB160 + 7.5µg H7N9, 1C) IB160 + 3.75µg H7N9, 2A) SE + 15µg H7N9, 2B) SE + 7.5µg H7N9, 2C) SE + 3.75µg H7N9, 3) unadjuvanted vaccine 15µg H7N9 and 4) placebo. Immunogenicity was evaluated through haemagglutination inhibition (HI) and microneutralization (MN) tests. Safety was evaluated by monitoring local and systemic, solicited and unsolicited adverse events (AE) and reactions (AR) 7 and 28 days after each study injection, respectively, whereas serious adverse events (SAE) were monitored up to 194 days post-second dose. A greater increase in antibody geometric mean titers (GMT) was observed in groups receiving adjuvanted vaccines. Vaccinees receiving IB160-adjuvanted formulations showed the greatest response in group 1B, which induced an HI GMT increase of 4.7 times, HI titers ≥40 in 45.2% of participants (MN titers ≥40 in 80.8%). Vaccinees receiving SE-adjuvanted vaccines showed the greatest response in group 2A, with an HI GMT increase of 2.5 times, HI titers ≥40 in 22.9% of participants (MN titers ≥40 in 65.7%). Frequencies of AE and AR were similar among groups. Pain at the administration site and headache were the most frequent local and systemic solicited ARs. The vaccine candidates were safe and the adjuvanted formulations have a potential dose-sparing effect on immunogenicity against influenza A/H7N9. The magnitude of this effect could be further explored.

Reduced seroprotection after pandemic H1N1 influenza adjuvant-free vaccination in patients with rheumatoid arthritis: implications for clinical practice.

BACKGROUND: Reduced response to pandemic (2009) H1N1 (pH1N1) vaccine in patients with rheumatoid arthritis (RA) was recently reported. OBJECTIVES: To evaluate the contribution of age, disease activity, medication and previous antibody levels to this reduced response. METHODS: 340 adult RA patients and 234 healthy controls were assessed before and 21 days after adjuvant-free influenza A/California/7/2009 (pH1N1) vaccine. Disease activity (DAS28), current treatment and pH1N1 antibody titres were collected. Seroprotection, seroconversion and factor increase in geometric mean titre (GMT) were calculated and adverse events registered. RESULTS: RA and controls showed similar (p>0.05) prevaccination GMT (8.0 vs 9.3) and seroprotection (10.8% vs 11.5%). After vaccination a significant reduction (p<0.001) was observed in all endpoints: GMT and factor increase in GMT, seroprotection and seroconversion rates. Disease activity did not preclude seroconversion or seroprotection and remained unchanged in 97.4% of patients. Methotrexate was the only disease-modifying antirheumatic drug associated with reduced responses (p=0.001). Vaccination was well tolerated. CONCLUSIONS: The data confirmed both short-term anti-pH1N1 vaccine safety and, different from most studies with seasonal influenza, reduced seroprotection in RA patients, unrelated to disease activity and to most medications (except methotrexate). Extrapolation of immune responses from one vaccine to another may therefore not be possible and specific immunisation strategies (possibly booster) may be needed. Clinicaltrials.gov no NCT01151644.