Homologous and Heterologous Covid-19 Booster Vaccinations.

BACKGROUND: Although the three vaccines against coronavirus disease 2019 (Covid-19) that have received emergency use authorization in the United States are highly effective, breakthrough infections are occurring. Data are needed on the serial use of homologous boosters (same as the primary vaccine) and heterologous boosters (different from the primary vaccine) in fully vaccinated recipients. METHODS: In this phase 1-2, open-label clinical trial conducted at 10 sites in the United States, adults who had completed a Covid-19 vaccine regimen at least 12 weeks earlier and had no reported history of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection received a booster injection with one of three vaccines: mRNA-1273 (Moderna) at a dose of 100 µg, Ad26.COV2.S (Johnson & Johnson-Janssen) at a dose of 5×1010 virus particles, or BNT162b2 (Pfizer-BioNTech) at a dose of 30 µg. The primary end points were safety, reactogenicity, and humoral immunogenicity on trial days 15 and 29. RESULTS: Of the 458 participants who were enrolled in the trial, 154 received mRNA-1273, 150 received Ad26.COV2.S, and 153 received BNT162b2 as booster vaccines; 1 participant did not receive the assigned vaccine. Reactogenicity was similar to that reported for the primary series. More than half the recipients reported having injection-site pain, malaise, headache, or myalgia. For all combinations, antibody neutralizing titers against a SARS-CoV-2 D614G pseudovirus increased by a factor of 4 to 73, and binding titers increased by a factor of 5 to 55. Homologous boosters increased neutralizing antibody titers by a factor of 4 to 20, whereas heterologous boosters increased titers by a factor of 6 to 73. Spike-specific T-cell responses increased in all but the homologous Ad26.COV2.S-boosted subgroup. CD8+ T-cell levels were more durable in the Ad26.COV2.S-primed recipients, and heterologous boosting with the Ad26.COV2.S vaccine substantially increased spike-specific CD8+ T cells in the mRNA vaccine recipients. CONCLUSIONS: Homologous and heterologous booster vaccines had an acceptable safety profile and were immunogenic in adults who had completed a primary Covid-19 vaccine regimen at least 12 weeks earlier. (Funded by the National Institute of Allergy and Infectious Diseases; DMID 21-0012 ClinicalTrials.gov number, NCT04889209.).

Safety and Immunogenicity of a Delayed Heterologous Avian Influenza A(H7N9) Vaccine Boost Following Different Priming Regimens: A Randomized Clinical Trial.

BACKGROUND: Influenza A (H7N9) has caused multiple disease waves with evidence of strain diversification. Optimal influenza A (H7N9) prime-boost vaccine strategies are unknown. METHODS: We recruited participants who had received monovalent inactivated A/Shanghai/2/2013 (H7N9) vaccine (MIV) approximately 5 years earlier, as follows: MIV with MF59 (MF59 × 2 group), MIV with AS03 (AS03 × 2 group), unadjuvanted MIV (No Adj group), MIV with MF59 or AS03 followed by unadjuvanted MIV (Adjx1 group), and A/H7-naive (unprimed group). Participants were randomized to receive 1 dose of AS03-adjuvanted or unadjuvanted A/Hong Kong/125/2017 (H7N9) MIV and were followed for safety and immunogenicity using hemagglutination inhibition (HAI) and neutralizing antibody assays. RESULTS: We enrolled 304 participants: 153 received the adjuvanted boost and 151 received the unadjuvanted boost. At 21 days postvaccination, the proportion of participants with HAI antibody titers against the boosting vaccine strain of ≥40 in the adjuvanted and unadjuvanted arms, respectively, were 88% and 49% in MF59 × 2 group, 89% and 75% in AS03 × 2 group, 59% and 20% in No Adj group, 94% and 55% in Adjx1group, and 9% and 11% in unprimed group. CONCLUSIONS: Serologic responses to a heterologous A(H7N9) MIV boost were highest in participants primed and boosted with adjuvant-containing regimens. CLINICAL TRIALS REGISTRATION: NCT03738241.

Disseminated vaccine-induced varicella infection in a kidney transplant recipient.

A 33-year-old kidney transplant (KT) recipient presented with a disseminated pruritic, painful, vesicular rash and hepatitis 3 weeks after receiving a varicella vaccine (VAR). A skin lesion biopsy sent to the Centers for Disease Control and Prevention for genotyping confirmed vaccine-strain varicella-zoster virus (VZV) (Oka strain; vOka). The patient was successfully treated with intravenous acyclovir during a prolonged hospital stay. This case supports the contraindication of VAR in adult KT recipients and highlights the potential for severe illness when used in this population. Optimally, VZV-seronegative KT candidates should receive VAR before starting immunosuppressive medications. If this opportunity is missed, the recombinant varicella-zoster vaccine might be considered following transplantation as it is already recommended to prevent herpes zoster in VZV-seropositive immunocompromised adults. Further study is needed as data are limited on the safety and efficacy of recombinant varicella-zoster vaccine for primary varicella prevention in VZV-seronegative immunocompromised adults.

Functional Evaluation and Genetic Evolution of Human T-Cell Responses After Vaccination With a Conditionally Replication-Defective Cytomegalovirus Vaccine.

BACKGROUND: Cytomegalovirus (CMV) can cause congenital infection and is the leading cause of nongenetic newborn disabilities. V160, a conditionally replication-defective virus, is an investigational vaccine under evaluation for prevention of congenital CMV. The vaccine was well tolerated and induced both humoral and cellular immunity in CMV-seronegative trial participants. T-cell-mediated immunity is important for immune control of CMV. Here we describe efforts to understand the quality attributes of the T-cell responses induced by vaccination. METHODS: Using multicolor flow cytometry, we analyzed vaccine-induced T cells for memory phenotype, antigen specificity, cytokine profiles, and cytolytic potential. Moreover, antigen-specific T cells were sorted from 4 participants, and next-generation sequencing was used to trace clonal lineage development during the course of vaccination using T-cell receptor ß-chain sequences as identifiers. RESULTS: The results demonstrated that vaccination elicited polyfunctional CD4 and CD8 T cells to 2 dominant antigens, pp65 and IE1, with a predominantly effector phenotype. Analysis of T-cell receptor repertoires showed polyclonal expansion of pp65- and IE1-specific T cells after vaccination. CONCLUSION: V160 induced a genetically diverse and polyfunctional T-cell response and the data support further clinical development of V160 for prevention of CMV infection and congenital transmission. CLINICAL TRIALS REGISTRATION: NCT01986010.

Quantitative and qualitative assessment of an all-inclusive postpartum human papillomavirus vaccination program.

BACKGROUND: A postpartum human papillomavirus vaccination program was locally implemented to address low initiation rates among young adults. Within 20 months, the program achieved high vaccine initiation and series completion rates. Based on the program's success, it was expanded to all 36 counties served by a public hospital. OBJECTIVE: This study aimed to conduct a quantitative and qualitative evaluation to examine the success and limitations of the program when expanded from 1 county to 36 counties, many of which are home to rural and medically underserved communities. STUDY DESIGN: Patient navigators reviewed the electronic medical records and immunization registry records of women aged ≤26 years, who delivered an infant at the public hospital, to determine whether they needed to initiate or complete the human papillomavirus vaccine series. Eligible women were counseled and offered the human papillomavirus vaccine during their hospital stay. Patient navigators scheduled follow-up injections in addition to the mother's postpartum or her infant's well-child visits, made reminder phone calls, and rescheduled missed appointments. Descriptive statistics, including frequencies and proportions, were used for patients approached in the initial and expansion programs. Frequencies from the initial and expansion programs were examined separately. Qualitative interviews were conducted with the clinic staff to evaluate the program. The qualitative analyses were conducted using NVivo (QSR International, Melbourne, Australia, version 10). RESULTS: Both initial and expanded programs achieved vaccine completion rates above 70%. Of the 2631 eligible postpartum women enrolled in the initial program, 785 (30%) had already been fully vaccinated. Of the remaining 1846 women, 1265 (69%) women received their first dose, and 196 (11%) women received their second or third dose on the postpartum unit. Of the 1461 women who received at least 1 dose through the initial program, 1124 (77%) completed all 3 doses. Of the 4330 eligible postpartum women enrolled in the expanded program, 886 (21%) had already been fully vaccinated. Of the remaining 3444 women, 2284 (66%) received their first dose, and 343 (10%) received their second or third dose on the postpartum unit. Of the 2627 women receiving at least 1 dose through the expanded program, 1932 (74%) completed all 3 doses. Clinic staff interviewed felt the program benefited the postpartum unit and clinics, because it increased patient knowledge of the vaccine, increased patient volume for vaccination, and gave healthcare providers more time to focus on other tasks. CONCLUSION: Human papillomavirus vaccination on the postpartum unit is an effective way to increase catchup rates and is well accepted by healthcare providers. High completion rates can be achieved if adequate support is provided, even among patients residing in rural or underserved areas who need extensive support to access primary healthcare services. Although this particular program may be considered costly, it is overall effective because the vaccine prevents 5 different types of cancer in women. The inclusion of human papillomavirus vaccination in routine postpartum care is a relatively easy way to reach many adults not vaccinated at a younger age and could help address low vaccination rates among young women in the United States, including hard-to-reach populations.

A Replication-Defective Human Cytomegalovirus Vaccine Elicits Humoral Immune Responses Analogous to Those with Natural Infection.

Human cytomegalovirus (HCMV) can cause congenital infections, which are a leading cause of childhood disabilities. Since the rate of maternal-fetal transmission is much lower in naturally infected (HCMV-seropositive) women, we hypothesize that a vaccine candidate capable of eliciting immune responses analogous to those of HCMV-seropositive subjects may confer protection against congenital HCMV. We have previously described a replication-defective virus vaccine based on strain AD169 (D. Wang, D. C. Freed, X. He, F. Li, et al., Sci Transl Med 8:362ra145, 2016, https://doi.org/10.1126/scitranslmed.aaf9387). The vaccine, named V160, has been shown to be safe and immunogenic in HCMV-seronegative human subjects, eliciting both humoral and cellular immune responses (S. P. Adler, S. E. Starr, S. A. Plotkin, S. H. Hempfling, et al., J Infect Dis 220:411-419, 2019, https://doi.org/10.1093/infdis/171.1.26). Here, we further showed that sera from V160-immunized HCMV-seronegative subjects have attributes similar in quality to those from seropositive subjects, including high-avidity antibodies to viral antigens, coverage against a panel of genetically distinct clinical isolates, and protection against viral infection in diverse types of human cells in culture. More importantly, vaccination appeared efficient in priming the human immune system, inducing memory B cells in six V160 recipients at frequencies comparable to those of three HCMV-seropositive subjects. Our results demonstrate the ability of V160 to induce robust and durable humoral memory responses to HCMV, justifying further clinical evaluation of the vaccine against congenital HCMV.IMPORTANCEIn utero HCMV infection can lead to miscarriage or childhood disabilities, and an effective vaccine is urgently needed. Since children born to women who are seropositive prior to pregnancy are less likely to be affected by congenital HCMV infection, it has been hypothesized that a vaccine capable of inducing an immune response resembling the responses in HCMV-seropositive women may be effective. We previously described a replication-defective virus vaccine that has been demonstrated safe and immunogenic in HCMV-seronegative subjects. Here, we conducted additional analyses to show that the vaccine can induce antibodies with functional attributes similar to those from HCMV-seropositive subjects. Importantly, vaccination can induce long-lived memory B cells at frequencies comparable to those seen in HCMV-seropositive subjects. We conclude that this vaccine is a promising candidate that warrants further clinical evaluation for prevention of congenital HCMV.

Prenatal vaccination of mothers and hepatitis B vaccination of their infants.

Tetanus, diphtheria, and acellular pertussis (Tdap) vaccination and influenza vaccination are recommended during pregnancy primarily to prevent influenza and pertussis in mothers and their infants. This study examines associations between prenatal Tdap vaccination and influenza vaccination of mothers and hepatitis B vaccination of their infants. A retrospective cohort study was conducted using data from electronic medical records from 15,468 deliveries to 14,925 mothers occurring April 2, 2014-December 3, 2016 at a university hospital in Texas. Hepatitis B vaccine receipt in the first 3 days of life was dichotomized. Margins post-estimation commands in Stata SE 15.1 were used to obtain predicted probabilities and risk differences after estimating odds ratios in logistic regression with robust variance estimates. Adjusted models included maternal age, race/ethnicity, Medicaid use, year of delivery, parity, and gravidity. Infants of mothers who received prenatal influenza vaccination in the 2014-2015 and 2015-2016 influenza seasons were more likely than those of mothers who did not to receive a hepatitis B vaccine in their first 3 days of life (adjusted risk difference (RD) 2.8%, 95% confidence interval (CI) 1.5-4.1% and RD 2.2%, 95% CI 0.9-3.5%, respectively). Hepatitis B vaccination was also higher among infants of Tdap-eligible mothers who received prenatal Tdap vaccination during pregnancy compared to those of mothers who did not (adjusted RD 9.1%, 95% CI 7.6-10.5%). Overall, prenatal vaccination was significantly associated with uptake of infant hepatitis B vaccine.

A human papillomavirus vaccination program for low-income postpartum women.

BACKGROUND: Effective interventions are needed to address the low rate of human papillomavirus (HPV) vaccination in the United States, particularly among girls and women 16-26 years old. Counseling and offering the vaccine to postpartum patients could be an effective strategy to increase uptake among young women who did not complete the 3-dose series at an earlier age. OBJECTIVE: The purpose of this evaluation was to assess the effectiveness of a multicomponent program designed for postpartum women that used patient navigators (PNs) and reminders for follow-up visits to improve uptake and completion of the HPV vaccine series. STUDY DESIGN: As part of standard care, patients ≤26 years of age from Galveston County, Texas, who delivered an infant from November 2012 through June 2014 at a public hospital were counseled and offered the HPV vaccine postpartum. PNs assisted with scheduling follow-up injections during postpartum or well-child visits. A program evaluation was conducted after 20 months. RESULTS: Of 1038 patients approached, only 161 (15.5%) had previously completed the vaccine series. Of the 877 patients who had not completed the series, 661 (75.4%) received at least 1 dose postpartum, with 575 patients receiving their first dose and 86 receiving their second or third doses. By April 2015, initiation rates had increased as a result of this program from 25.4% before the program was initiated to 80.8% and completion rates from 15.5-65.1%. Missed appointments for injections were less likely among those who received text message reminders and more likely among those with ≥2 prior pregnancies. Those who were Hispanic or had received an influenza vaccination in the last year were more likely to initiate and complete the series through this program. Patients who missed ≥1 follow-up appointments were less likely to complete the vaccine series. CONCLUSION: Offering the HPV vaccine postpartum dramatically increased initiation rates among postpartum patients. PN and text messages ensured that a high percentage completed all 3 doses.

Implementation of a Postpartum HPV Vaccination Program in a Southeast Texas Hospital: A Qualitative Study Evaluating Health Care Provider Acceptance.

Introduction The objective of this qualitative study was to assess healthcare providers' acceptability of an ongoing postpartum human papillomavirus (HPV) vaccination program in Southeast Texas and its integration into everyday clinical care. Methods In 2012, the Department of Obstetrics & Gynecology at the University of Texas Medical Branch (UTMB) began offering HPV vaccination as part of standard postpartum care to increase vaccination rates among young women in Galveston County. Initial vaccine doses were offered on the postpartum unit while subsequent doses were coordinated with postpartum and well-baby visits. Thirty months after project initiation, semi-structured interviews of physicians (n = 12) and nurses (n = 6) involved in postpartum and pediatric care at UTMB were conducted. Interview transcripts were analyzed using thematic analysis in Nvivo10. Results Overall, providers demonstrated "pro-vaccine" attitudes and stated the program was an effective strategy for vaccinating hard-to-reach women. Cancer prevention was the main perceived benefit while follow-up compliance was the primary perceived patient barrier. The initial challenges with integrating postpartum HPV vaccination included miscommunication between providers regarding vaccine orders and coordination issues with well-baby visits for follow-up doses. One novel finding was providers' beliefs that women's personal HPV vaccine practices may positively impact their decisions about later vaccinating their children against HPV. Providers' suggestions to improve the program included: enhancing postpartum HPV vaccine education for patients, offering more continuing education for providers, and increasing community awareness of HPV vaccination. Discussion These findings can help providers of postpartum care understand how to integrate postpartum HPV vaccination into their current practices and how to overcome perceived vaccination barriers.

Assessing the need for and acceptability of a free-of-charge postpartum HPV vaccination program.

OBJECTIVE: Human papillomavirus (HPV) vaccine uptake rate among young adult US women was only 23% in 2010. One way to improve this low rate is to administer the vaccine postpartum. We examined whether this population requires vaccination and whether they would be agreeable to receiving it free of charge after delivery. STUDY DESIGN: Women 26 years of age or younger seeking prenatal care in publicly funded clinics in southeast Texas were interviewed in 2012 regarding their HPV vaccination status, barriers to vaccination, and whether they would be willing to receive this vaccine postpartum if offered free of charge. Medical charts were reviewed to extract additional information. RESULTS: Overall, 13.0% (65 of 500) stated they had initiated and 7.6% (38 of 500) completed the 3-dose vaccine series. Ethnic differences were noted with 21.0% of non-Hispanic whites, 14.6% of blacks, and 9.3% of Hispanics (P = .002) initiating the vaccine and 13.5%, 7.8%, and 5.2% (P = .006) competing all 3 doses, respectively. Lowest initiation (4.2%) and completion (1.4%) rates were observed among recently immigrated Hispanic women. Those who had not graduated from high school and older women were less likely to have been vaccinated. Almost 83% of those who had not received any HPV doses or completed the series were willing to receive the injection free of charge in the hospital after their delivery. CONCLUSION: HPV vaccine uptake rates are very low among women receiving prenatal care in southeast Texas. Offering this vaccine free of charge to postpartum women could be an effective strategy in this population because 5 of 6 women favored receiving it in this setting.

Immunogenicity of 2 or 3 Doses of 9vHPV Vaccine in U.S. Female Individuals 15 to 26 Years of Age.

BACKGROUND: Within the United States, a 9-valent human papillomavirus (9vHPV) vaccine (HPV-6/11/16/18/31/33/45/52/58) is recommended as a two-dose series among individuals 9 to 14 years of age and a three-dose series among those 15 to 26 years of age. Data comparing two versus three doses of 9vHPV vaccine among individuals 15 to 26 years of age are limited. METHODS: We report on an ongoing, single-blinded, randomized noninferiority trial of the 9vHPV vaccine among individuals 15 to 26 years of age in the United States. Participants were randomly assigned to a two-dose (0 and 6 months) or three-dose (0, 2, and 6 months) schedule. Blood draws to assess antibody titers were planned before the first vaccination and at 1 and 6 months after the final vaccination. The primary outcome was the rate of seroconversion at 1 month after final vaccination. The secondary outcome was the two-dose versus three-dose ratio of antibody geometric mean titers (GMTs) for each of the 9vHPV genotypes at 1 and 6 months after final vaccination. This interim analysis reports results of female participants at 1 month after final vaccination. RESULTS: Of 860 participants screened, 438 were enrolled and randomly assigned to the two-dose (n=217) or three-dose (n=221) group. At 1 month after the final vaccine dose, the seroconversion rate for each of the nine HPV genotypes in the vaccine was 100% among participants in the two-dose group and 99% in the three-dose group. The point estimates of the two-dose versus three-dose ratios of antibody GMTs for eight of the nine HPV genotypes were above unity; the ratio for HPV-45 was 0.86 (95% confidence interval [CI], 0.66 to 1.13). This was also the smallest value for the lower bound of the 95% CI for all nine ratios (ratios above 1 favor the two-dose schedule). No serious adverse events were observed. CONCLUSIONS: In this unplanned interim analysis of U.S. female participants 15 to 26 years of age, two doses of 9vHPV vaccine appear to elicit responses similar to three doses at 1 month postvaccination. We await final results at 6 months following the last vaccine dose. (ClinicalTrials.gov number, NCT03943875.)

Transcriptional signature of durable effector T cells elicited by a replication defective HCMV vaccine.

Human cytomegalovirus (HCMV) is a leading infectious cause of birth defects and the most common opportunistic infection that causes life-threatening diseases post-transplantation; however, an effective vaccine remains elusive. V160 is a live-attenuated replication defective HCMV vaccine that showed a 42.4% efficacy against primary HCMV infection among seronegative women in a phase 2b clinical trial. Here, we integrated the multicolor flow cytometry, longitudinal T cell receptor (TCR) sequencing, and single-cell RNA/TCR sequencing approaches to characterize the magnitude, phenotype, and functional quality of human T cell responses to V160. We demonstrated that V160 de novo induces IE-1 and pp65 specific durable polyfunctional effector CD8 T cells that are comparable to those induced by natural HCMV infection. We identified a variety of V160-responsive T cell clones which exhibit distinctive "transient" and "durable" expansion kinetics, and revealed a transcriptional signature that marks durable CD8 T cells post-vaccination. Our study enhances the understanding of human T-cell immune responses to V160 vaccination.

Safety and immune responses in children after concurrent or sequential 2009 H1N1 and 2009-2010 seasonal trivalent influenza vaccinations.

BACKGROUND: Administering 2 separate vaccines for seasonal and pandemic influenza was necessary in 2009. Therefore, we conducted a randomized trial of monovalent 2009 H1N1 influenza vaccine (2009 H1N1 vaccine) and seasonal trivalent inactivated influenza vaccine (TIV; split virion) given sequentially or concurrently in previously vaccinated children. METHODS: Children randomized to 4 study groups and stratified by age received 1 dose of seasonal TIV and 2 doses of 2009 H1N1 vaccine in 1 of 4 combinations. Injections were given at 21-day intervals and serum samples for hemagglutination inhibition antibody responses were obtained prior to and 21 days after each vaccination. Reactogenicity and adverse events were monitored. RESULTS: All combinations of vaccines were safe in the 531 children enrolled. Generally, 1 dose of 2009 H1N1 vaccine and 1 dose of TIV, regardless of sequence or concurrency of administration, was immunogenic in children ≥ 10 years of age; children <10 years of age required 2 doses of 2009 H1N1 vaccine. CONCLUSIONS: Vaccines were generally well tolerated. The immune responses to 2009 H1N1 vaccine were adequate regardless of the sequence of vaccination in all age groups but the sequence affected titers to TIV antigens. Two doses of 2009 H1N1 vaccine were required to achieve a protective immune response in children <10 years of age. CLINICAL TRIALS REGISTRATION: NCT00943202.

Immunogenicity of NVX-CoV2373 heterologous boost against SARS-CoV-2 variants.

As part of a multicenter study evaluating homologous and heterologous COVID-19 booster vaccines, we assessed the magnitude, breadth, and short-term durability of binding and pseudovirus-neutralizing antibody (PsVNA) responses following a single booster dose of NVX-CoV2373 in adults primed with either Ad26.COV2.S, mRNA-1273, or BNT162b2 vaccines. NVX-CoV2373 as a heterologous booster was immunogenic and associated with no safety concerns through Day 91. Fold-rises in PsVNA titers from baseline (Day 1) to Day 29 were highest for prototypic D614G variant and lowest for more recent Omicron sub-lineages BQ.1.1 and XBB.1. Peak humoral responses against all SARS-CoV-2 variants were lower in those primed with Ad26.COV2.S than with mRNA vaccines. Prior SARS CoV-2 infection was associated with substantially higher baseline PsVNA titers, which remained elevated relative to previously uninfected participants through Day 91. These data support the use of heterologous protein-based booster vaccines as an acceptable alternative to mRNA or adenoviral-based COVID-19 booster vaccines. This trial was conducted under ClinicalTrials.gov: NCT04889209.

Human papillomavirus dose reminder preferences among parents from a diverse clinical sample: a qualitative study.

Reminders are an important method for encouraging patients to return for follow-up visits, such as for successive doses of the human papillomavirus (HPV) vaccine. However, patients may have preferences for different types of reminders. This study examined which reminder methods parents of pediatric patients found most useful and their thoughts on how the reminders helped them to complete their children's HPV vaccine series. This qualitative study was conducted on a purposively sampled group of parents who participated in a multi-level intervention intended to improve uptake and completion of the HPV vaccine series. Parents who agreed to participate were interviewed by phone using semi-structured interviews about their satisfaction with different program components, including reminders they received. Interviews were conducted between May 26, 2016 and October 18, 2017. Thematic analyses of data were conducted using NVivo software. Among 269 program participants invited to participate in the interviews, 157 agreed (58.4%) and 89 were successfully interviewed (33.1%). Participants thought that reminders were effective at helping them return for follow-up visits to ensure their children received all recommended HPV vaccine doses. Although most parents preferred texts, many also favored other reminder methods by themselves or in combination with texts. Parents suggested that the reminders indicate the purpose of the appointment and for which child. Reminders are an important part of a multi-component intervention that aims to increase completion of the HPV vaccine series. Program enrollees prefer different types of reminders, so offering several options may improve returns for follow-up doses.

A phase I randomized, double-blind, placebo-controlled study to evaluate the safety, tolerability, and immunogenicity of a live-attenuated quadrivalent dengue vaccine in flavivirus-naïve and flavivirus-experienced healthy adults.

Dengue (DENV) is a mosquito-borne virus with four serotypes causing substantial morbidity in tropical and subtropical areas worldwide. V181 is an investigational, live, attenuated, quadrivalent dengue vaccine. In this phase 1 double-blind, placebo-controlled study, the safety, tolerability, and immunogenicity of V181 in baseline flavivirus-naïve (BFN) and flavivirus-experienced (BFE) healthy adults were evaluated in two formulations: TV003 and TV005. TV005 contains a 10-fold higher DENV2 level than TV003. Two-hundred adults were randomized 2:2:1 to receive TV003, TV005, or placebo on Days 1 and 180. Immunogenicity against the 4 DENV serotypes was measured using a Virus Reduction Neutralization Test (VRNT60) after each vaccination and out to 1 year after the second dose. There were no discontinuations due to adverse events (AE) or serious vaccine-related AEs in the study. Most common AEs after TV003 or TV005 were headache, rash, fatigue, and myalgia. Tri- or tetravalent vaccine-viremia was detected in 63.9% and 25.6% of BFN TV003 and TV005 participants, respectively, post-dose 1 (PD1). Tri- or tetravalent dengue VRNT60 seropositivity was demonstrated in 92.6% of BFN TV003, 74.2% of BFN TV005, and 100% of BFE TV003 and TV005 participants PD1. Increases in VRNT60 GMTs were observed after the first vaccination with TV003 and TV005 in both flavivirus subgroups for all dengue serotypes, and minimal increases were measured PD2. GMTs in the TV003 and TV005 BFE and BFN groups remained above the respective baselines and placebo through 1-year PD2. These data support further development of V181 as a single-dose vaccine for the prevention of dengue disease.

Rapid decline in vaccine-boosted neutralizing antibodies against SARS-CoV-2 Omicron variant.

The Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exhibits reduced susceptibility to vaccine-induced neutralizing antibodies, requiring a boost to generate protective immunity. We assess the magnitude and short-term durability of neutralizing antibodies after homologous and heterologous boosting with mRNA and Ad26.COV2.S vaccines. All prime-boost combinations substantially increase the neutralization titers to Omicron, although the boosted titers decline rapidly within 2 months from the peak response compared with boosted titers against the prototypic D614G variant. Boosted Omicron neutralization titers are substantially higher for homologous mRNA vaccine boosting, and for heterologous mRNA and Ad26.COV2.S vaccine boosting, compared with homologous Ad26.COV2.S boosting. Homologous mRNA vaccine boosting generates nearly equivalent neutralizing activity against Omicron sublineages BA.1, BA.2, and BA.3 but modestly reduced neutralizing activity against BA.2.12.1 and BA.4/BA.5 compared with BA.1. These results have implications for boosting requirements to protect against Omicron and future variants of SARS-CoV-2. This trial was conducted under ClincalTrials.gov: NCT04889209.

A conditionally replication-defective cytomegalovirus vaccine elicits potent and diverse functional monoclonal antibodies in a phase I clinical trial.

A conditionally replication-defective human cytomegalovirus (HCMV) vaccine, V160, was shown to be safe and immunogenic in a two-part, double-blind, randomized, placebo-controlled phase I clinical trial (NCT01986010). However, the specificities and functional properties of V160-elicited antibodies remain undefined. Here, we characterized 272 monoclonal antibodies (mAbs) isolated from single memory B cells of six V160-vaccinated subjects. The mAbs bind to diverse HCMV antigens, including multiple components of the pentamer, gB, and tegument proteins. The most-potent neutralizing antibodies target the pentamer-UL subunits. The binding sites of the antibodies overlap with those of antibodies responding to natural HCMV infection. The majority of the neutralizing antibodies target the gHgL subunit. The non-neutralizing antibodies predominantly target the gB and pp65 proteins. Sequence analysis indicated that V160 induced a class of gHgL antibodies expressing the HV1-18/KV1-5 germline genes in multiple subjects. This study provides valuable insights into primary targets for anti-HCMV antibodies induced by V160 vaccination.

Heterologous SARS-CoV-2 Booster Vaccinations - Preliminary Report.

Background: While Coronavirus disease 2019 (Covid-19) vaccines are highly effective, breakthrough infections are occurring. Booster vaccinations have recently received emergency use authorization (EUA) for certain populations but are restricted to homologous mRNA vaccines. We evaluated homologous and heterologous booster vaccination in persons who had received an EUA Covid-19 vaccine regimen. Methods: In this phase 1/2 open-label clinical trial conducted at ten U.S. sites, adults who received one of three EUA Covid-19 vaccines at least 12 weeks prior to enrollment and had no reported history of SARS-CoV-2 infection received a booster injection with one of three vaccines (Moderna mRNA-1273 100-µg, Janssen Ad26.COV2.S 5×1010 virus particles, or Pfizer-BioNTech BNT162b2 30-µg; nine combinations). The primary outcomes were safety, reactogenicity, and humoral immunogenicity on study days 15 and 29. Results: 458 individuals were enrolled: 154 received mRNA-1273, 150 received Ad26.CoV2.S, and 153 received BNT162b2 booster vaccines. Reactogenicity was similar to that reported for the primary series. Injection site pain, malaise, headache, and myalgia occurred in more than half the participants. Booster vaccines increased the neutralizing activity against a D614G pseudovirus (4.2-76-fold) and binding antibody titers (4.6-56-fold) for all combinations; homologous boost increased neutralizing antibody titers 4.2-20-fold whereas heterologous boost increased titers 6.2-76-fold. Day 15 neutralizing and binding antibody titers varied by 28.7-fold and 20.9-fold, respectively, across the nine prime-boost combinations. Conclusion: Homologous and heterologous booster vaccinations were well-tolerated and immunogenic in adults who completed a primary Covid-19 vaccine regimen at least 12 weeks earlier.

An educational intervention to improve attitudes regarding HPV vaccination and comfort with counseling among US medical students.

Many medical students are not comfortable recommending the human papillomavirus (HPV) vaccine because they do not feel prepared to discuss it with their patients. A prior study demonstrated that this is particularly a problem among unvaccinated students. Our purpose was to determine if medical student attitudes and comfort with counseling could be improved by attending a single lecture delivered by an expert on the topic. To assess the effects of the educational program, we conducted pre- and posttests on medical students before and after a single lecture on HPV vaccination. Changes in items related to attitude and comfort were examined. Student characteristics associated with changes in scores were also examined and compared. A total of 256 medical students participated in the pre- and posttests. Before the lecture, students demonstrated low knowledge of HPV vaccination and did not feel comfortable counseling parents of younger patients. However, students <30 years of age demonstrated significant improvements after the lecture in comfort. Asian and Hispanic students showed the greatest improvement in comfort with counseling, as did students who reported they had not received the HPV vaccine. Attending a single lecture given by an expert can improve medical students' attitudes and comfort with HPV vaccine counseling, especially if the students were not vaccinated themselves. This study suggests that including material on HPV vaccination in the standard medical student curriculum could help increase physician recommendation for the HPV vaccine.