Immunogenicity of COVID-19 mRNA Vaccines in Pregnant and Lactating Women.

Importance: Pregnant women are at increased risk of morbidity and mortality from COVID-19 but have been excluded from the phase 3 COVID-19 vaccine trials. Data on vaccine safety and immunogenicity in these populations are therefore limited. Objective: To evaluate the immunogenicity of COVID-19 messenger RNA (mRNA) vaccines in pregnant and lactating women, including against emerging SARS-CoV-2 variants of concern. Design, Setting, and Participants: An exploratory, descriptive, prospective cohort study enrolled 103 women who received a COVID-19 vaccine from December 2020 through March 2021 and 28 women who had confirmed SARS-CoV-2 infection from April 2020 through March 2021 (the last follow-up date was March 26, 2021). This study enrolled 30 pregnant, 16 lactating, and 57 neither pregnant nor lactating women who received either the mRNA-1273 (Moderna) or BNT162b2 (Pfizer-BioNTech) COVID-19 vaccines and 22 pregnant and 6 nonpregnant unvaccinated women with SARS-CoV-2 infection. Main Outcomes and Measures: SARS-CoV-2 receptor binding domain binding, neutralizing, and functional nonneutralizing antibody responses from pregnant, lactating, and nonpregnant women were assessed following vaccination. Spike-specific T-cell responses were evaluated using IFN-γ enzyme-linked immunospot and multiparameter intracellular cytokine-staining assays. Humoral and cellular immune responses were determined against the original SARS-CoV-2 USA-WA1/2020 strain as well as against the B.1.1.7 and B.1.351 variants. Results: This study enrolled 103 women aged 18 to 45 years (66% non-Hispanic White) who received a COVID-19 mRNA vaccine. After the second vaccine dose, fever was reported in 4 pregnant women (14%; SD, 6%), 7 lactating women (44%; SD, 12%), and 27 nonpregnant women (52%; SD, 7%). Binding, neutralizing, and functional nonneutralizing antibody responses as well as CD4 and CD8 T-cell responses were present in pregnant, lactating, and nonpregnant women following vaccination. Binding and neutralizing antibodies were also observed in infant cord blood and breast milk. Binding and neutralizing antibody titers against the SARS-CoV-2 B.1.1.7 and B.1.351 variants of concern were reduced, but T-cell responses were preserved against viral variants. Conclusion and Relevance: In this exploratory analysis of a convenience sample, receipt of a COVID-19 mRNA vaccine was immunogenic in pregnant women, and vaccine-elicited antibodies were transported to infant cord blood and breast milk. Pregnant and nonpregnant women who were vaccinated developed cross-reactive antibody responses and T-cell responses against SARS-CoV-2 variants of concern.

Immunogenicity of the Ad26.COV2.S Vaccine for COVID-19.

Importance: Control of the global COVID-19 pandemic will require the development and deployment of safe and effective vaccines. Objective: To evaluate the immunogenicity of the Ad26.COV2.S vaccine (Janssen/Johnson & Johnson) in humans, including the kinetics, magnitude, and phenotype of SARS-CoV-2 spike-specific humoral and cellular immune responses. Design, Setting, and Participants: Twenty-five participants were enrolled from July 29, 2020, to August 7, 2020, and the follow-up for this day 71 interim analysis was completed on October 3, 2020; follow-up to assess durability will continue for 2 years. This study was conducted at a single clinical site in Boston, Massachusetts, as part of a randomized, double-blind, placebo-controlled phase 1 clinical trial of Ad26.COV2.S. Interventions: Participants were randomized to receive 1 or 2 intramuscular injections with 5 × 1010 viral particles or 1 × 1011 viral particles of Ad26.COV2.S vaccine or placebo administered on day 1 and day 57 (5 participants in each group). Main Outcomes and Measures: Humoral immune responses included binding and neutralizing antibody responses at multiple time points following immunization. Cellular immune responses included immunospot-based and intracellular cytokine staining assays to measure T-cell responses. Results: Twenty-five participants were randomized (median age, 42; age range, 22-52; 52% women, 44% male, 4% undifferentiated), and all completed the trial through the day 71 interim end point. Binding and neutralizing antibodies emerged rapidly by day 8 after initial immunization in 90% and 25% of vaccine recipients, respectively. By day 57, binding and neutralizing antibodies were detected in 100% of vaccine recipients after a single immunization. On day 71, the geometric mean titers of spike-specific binding antibodies were 2432 to 5729 and the geometric mean titers of neutralizing antibodies were 242 to 449 in the vaccinated groups. A variety of antibody subclasses, Fc receptor binding properties, and antiviral functions were induced. CD4+ and CD8+ T-cell responses were induced. Conclusion and Relevance: In this phase 1 study, a single immunization with Ad26.COV2.S induced rapid binding and neutralization antibody responses as well as cellular immune responses. Two phase 3 clinical trials are currently underway to determine the efficacy of the Ad26.COV2.S vaccine. Trial Registration: ClinicalTrials.gov Identifier: NCT04436276.

Safety and immunogenicity of a Zika purified inactivated virus vaccine given via standard, accelerated, or shortened schedules: a single-centre, double-blind, sequential-group, randomised, placebo-controlled, phase 1 trial.

BACKGROUND: The development of an effective vaccine against Zika virus remains a public health priority. A Zika purified inactivated virus (ZPIV) vaccine candidate has been shown to protect animals against Zika virus challenge and to be well tolerated and immunogenic in humans up to 8 weeks of follow-up. We aimed to assess the safety and immunogenicity of ZPIV in humans up to 52 weeks of follow-up when given via standard or accelerated vaccination schedules. METHODS: We did a single-centre, double-blind, randomised controlled, phase 1 trial in healthy adults aged 18-50 years with no known history of flavivirus vaccination or infection at Beth Israel Deaconess Medical Center in Boston, MA, USA. Participants were sequentially enrolled into one of three groups: ZPIV given at weeks 0 and 4 (standard regimen), weeks 0 and 2 (accelerated regimen), or week 0 alone (single-dose regimen). Within each group, participants were randomly assigned using a computer-generated randomisation schedule to receive an intramuscular injection of 5 µg ZPIV or saline placebo, in a ratio of 5:1. The sponsor, clinical staff, investigators, participants, and laboratory personnel were masked to treatment assignment. The primary endpoint was safety up to day 364 after final dose administration, and secondary endpoints were proportion of participants with positive humoral immune responses (50% microneutralisation titre [MN50] ≥100) and geometric mean MN50 at observed peak response (ie, the highest neutralising antibody level observed for an individual participant across all timepoints) and week 28. All participants who received at least one dose of ZPIV or placebo were included in the safety population; the analysis of immunogenicity at observed peak included all participants who received at least one dose of ZPIV or placebo and had any adverse events or immunogenicity data after dosing. The week 28 immunogenicity analysis population consisted of all participants who received ZPIV or placebo and had immunogenicity data available at week 28. This trial is registered with ClinicalTrials.gov, NCT02937233. FINDINGS: Between Dec 8, 2016, and May 17, 2017, 12 participants were enrolled into each group and then randomly assigned to vaccine (n=10) or placebo (n=2). There were no serious or grade 3 treatment-related adverse events. The most common reactions among the 30 participants who received the vaccine were injection-site pain (24 [80%]), fatigue (16 [53%]), and headache (14 [46%]). A positive response at observed peak titre was detected in all participants who received ZPIV via the standard regimen, in eight (80%) of ten participants who received ZPIV via the accelerated regimen, and in none of the ten participants who received ZPIV via the single-dose regimen. The geometric mean of all individual participants' observed peak values was 1153·9 (95% CI 455·2-2925·2) in the standard regimen group, 517·7 (142·9-1875·6) in the accelerated regimen group, and 6·3 (3·7-10·8) in the single-dose regimen group. At week 28, a positive response was observed in one (13%) of eight participants who received ZPIV via the standard regimen and in no participant who received ZPIV via the accelerated (n=7) or single-dose (n=10) regimens. The geomteric mean titre (GMT) at this timepoint was 13·9 (95% CI 3·5-55·1) in the standard regimen group and 6·9 (4·0-11·9) in the accelerated regimen group; antibody titres were undetectable at 28 weeks in participants who received ZPIV via the single-dose regimen. For all vaccine schedules, GMTs peaked 2 weeks after the final vaccination and declined to less than 100 by study week 16. There was no difference in observed peak GMTs between the standard 4-week and the accelerated 2-week boosting regimens (p=0·4494). INTERPRETATION: ZPIV was safe and well tolerated in humans up to 52 weeks of follow-up. ZPIV immunogenicity required two doses and was not durable. Additional studies of ZPIV to optimise dosing schedules are ongoing. FUNDING: The Henry M Jackson Foundation for the Advancement of Military Medicine.

Comparison of shortened mosaic HIV-1 vaccine schedules: a randomised, double-blind, placebo-controlled phase 1 trial (IPCAVD010/HPX1002) and a preclinical study in rhesus monkeys (NHP 17-22).

BACKGROUND: Current efficacy studies of a mosaic HIV-1 prophylactic vaccine require four vaccination visits over one year, which is a complex regimen that could prove challenging for vaccine delivery at the community level, both for recipients and clinics. In this study, we evaluated the safety, tolerability, and immunogenicity of shorter, simpler regimens of trivalent Ad26.Mos.HIV expressing mosaic HIV-1 Env/Gag/Pol antigens combined with aluminium phosphate-adjuvanted clade C gp140 protein. METHODS: We did this randomised, double-blind, placebo-controlled phase 1 trial (IPCAVD010/HPX1002) at Beth Israel Deaconess Medical Center in Boston, MA, USA. We included healthy, HIV-uninfected participants (aged 18-50 years) who were considered at low risk for HIV infection and had not received any vaccines in the 14 days before study commencement. We randomly assigned participants via a computer-generated randomisation schedule and interactive web response system to one of three study groups (1:1:1) testing different regimens of trivalent Ad26.Mos.HIV (5 × 1010 viral particles per 0·5 mL) combined with 250 µg adjuvanted clade C gp140 protein. They were then assigned to treatment or placebo subgroups (5:1) within each of the three main groups. Participants and investigators were masked to treatment allocation until the end of the follow-up period. Group 1 received Ad26.Mos.HIV alone at weeks 0 and 12 and Ad26.Mos.HIV plus adjuvanted gp140 at weeks 24 and 48. Group 2 received Ad26.Mos.HIV plus adjuvanted gp140 at weeks 0, 12, and 24. Group 3 received Ad26.Mos.HIV alone at week 0 and Ad26.Mos.HIV plus adjuvanted gp140 at weeks 8 and 24. Participants in the control group received 0·5 mL of 0·9% saline. All study interventions were administered intramuscularly. The primary endpoints were Env-specific binding antibody responses at weeks 28, 52, and 72 and safety and tolerability of the vaccine regimens for 28 days after the injection. All participants who received at least one vaccine dose or placebo were included in the safety analysis; immunogenicity was analysed using the per-protocol population. The IPCAVD010/HPX1002 trial is registered with ClinicalTrials.gov, NCT02685020. We also did a parallel preclinical study in rhesus monkeys to test the protective efficacy of the shortened group 3 regimen. FINDINGS: Between March 7, 2016, and Aug 19, 2016, we randomly assigned 36 participants to receive at least one dose of study vaccine or placebo, ten to each vaccine group and two to the corresponding placebo group. 30 (83%) participants completed the full study, and six (17%) discontinued it prematurely because of loss to follow-up, withdrawal of consent, investigator decision, and an unrelated death from a motor vehicle accident. The two shortened regimens elicited comparable antibody titres against autologous clade C Env at peak immunity to the longer, 12-month regimen: geometric mean titre (GMT) 41 007 (95% CI 17 959-93 636) for group 2 and 49 243 (29 346-82 630) for group 3 at week 28 compared with 44 590 (19 345-102 781) for group 1 at week 52). Antibody responses remained increased (GMT >5000) in groups 2 and 3 at week 52 but were highest in group 1 at week 72. Antibody-dependent cellular phagocytosis, Env-specific IgG3, tier 1A neutralising activity, and broad cellular immune responses were detected in all groups. All vaccine regimens were well tolerated. Mild-to-moderate pain or tenderness at the injection site was the most commonly reported solicited local adverse event, reported by 28 vaccine recipients (93%) and two placebo recipients (33%). Grade 3 solicited systemic adverse events were reported by eight (27%) vaccine recipients and no placebo recipients; the most commonly reported grade 3 systemic symptoms were fatigue, myalgia, and chills. The shortened group 3 regimen induced comparable peak immune responses in 30 rhesus monkeys as in humans and resulted in an 83% (95% CI 38·7-95, p=0·004 log-rank test) reduction in per-exposure acquisition risk after six intrarectal challenges with SHIV-SF162P3 at week 54, more than 6 months after final vaccination. INTERPRETATION: Short, 6-month regimens of a mosaic HIV-1 prophylactic vaccine elicited robust HIV-specific immune responses that were similar to responses elicited by a longer, 12-month schedule. Preclinical data showed partial protective efficacy of one of the short vaccine regimens in rhesus monkeys. Further clinical studies are required to test the suitability of the shortened vaccine regimens in humans. Such shortened regimens would be valuable to increase vaccine delivery at the community level, particularly in resource-limited settings. FUNDING: Ragon Institute (Massachusetts General Hospital, Massachusetts Institute of Technology, and Harvard University; Cambridge, MA, USA) and Janssen Vaccines & Prevention (Leiden, Netherlands).