Comparing reactogenicity of COVID-19 vaccine boosters: a systematic review and meta-analysis.

INTRODUCTION: Different COVID-19 vaccines are being utilized as boosters. This systematic review and meta-analysis aims to evaluate the reactogenicity of COVID-19 vaccines given as booster doses, according to vaccine type, dose, timing, participant characteristics and primary immunization regimen received. METHODS: Four databases (MEDLINE, Embase, Web of Science and CENTRAL) were searched for randomized controlled trials between 1 January 2020 and 1 January 2023 according to predetermined criteria. RESULTS: Twenty-eight studies describing 19 vaccines of four different types (viral vector, inactivated, mRNA and protein sub-unit) were identified. BNT162b2 vaccine (Pfizer-BioNTech) was selected as the control as it was most often compared with other vaccines. Fever, fatigue, headache, injection-site pain, redness, and swelling were the most frequently reported solicited events. mRNA vaccines were the most reactogenic, followed by viral vector vaccines and protein sub-unit vaccines, while inactivated vaccines were the least reactogenic. Full-dose vaccines were more reactogenic than half-dose vaccines. Heterologous BNT162b2 boosters were more reactogenic than boosters with the same vaccine used for primary immunization. CONCLUSIONS: COVID-19 vaccine booster schedules have distinct reactogenicity profiles, dependent on dose and vaccine type, which may allow targeted recommendations and provide choice for specific populations. Greater standardization of adverse event reporting will aid future studies.

The predictive role of symptoms in COVID-19 diagnostic models: A longitudinal insight.

To investigate the symptoms of SARS-CoV-2 infection, their dynamics and their discriminatory power for the disease using longitudinally, prospectively collected information reported at the time of their occurrence. We have analysed data from a large phase 3 clinical UK COVID-19 vaccine trial. The alpha variant was the predominant strain. Participants were assessed for SARS-CoV-2 infection via nasal/throat PCR at recruitment, vaccination appointments, and when symptomatic. Statistical techniques were implemented to infer estimates representative of the UK population, accounting for multiple symptomatic episodes associated with one individual. An optimal diagnostic model for SARS-CoV-2 infection was derived. The 4-month prevalence of SARS-CoV-2 was 2.1%; increasing to 19.4% (16.0%-22.7%) in participants reporting loss of appetite and 31.9% (27.1%-36.8%) in those with anosmia/ageusia. The model identified anosmia and/or ageusia, fever, congestion, and cough to be significantly associated with SARS-CoV-2 infection. Symptoms' dynamics were vastly different in the two groups; after a slow start peaking later and lasting longer in PCR+ participants, whilst exhibiting a consistent decline in PCR- participants, with, on average, fewer than 3 days of symptoms reported. Anosmia/ageusia peaked late in confirmed SARS-CoV-2 infection (day 12), indicating a low discrimination power for early disease diagnosis.

Propositive follow-up: Long-term immune responses to the 4CMenB and MenACWY vaccines in people living with HIV.

BACKGROUND: People living with HIV have an increased risk of meningococcal disease. The Propositive trial evaluated co-administration of two doses of a four-component recombinant protein-based MenB vaccine (4CMenB) and a quadrivalent conjugate polysaccharide MenACWY vaccine (MenACWY-CRM197) given 1 month apart in people with HIV. The follow-up trial assessed the immunogenicity of these vaccines at 1.5 and 2.5 years after primary vaccination. METHODS: Participants who completed the parent Propositive trial were invited to the follow-up study. Immunogenicity analysis was performed at 18 and 30 months after primary vaccination. Primary outcome measures were serum bactericidal antibody (SBA) geometric mean titres (GMTs) against three MenB reference strains and the proportion of participants maintaining a protective SBA titre of ≥4 at 18 and 30 months. Secondary outcome measures were SBA GMTs against MenA, C, W, and Y serogroups and the proportion of participants maintaining a protective SBA titre of ≥8 at 18 and 30 months. The trial is registered with Clinicaltrials.gov (NCT042394300). RESULTS: A total of 40 participants aged 22-47 years were enrolled. Geometric mean titres waned by 18 and 30 months but remained higher than pre-vaccination for all MenB strains and MenA, C, W, and Y. In total, 75%-85% of participants retained protective SBA titres by 30 months against individual MenB strains, whereas 68.8% of patients retained protective antibody titres against all three MenB strains. Antibodies against MenC waned more rapidly than did those against MenA, W, and Y. The proportion of participants with protective titres against MenC at 30 months was also lower (46.9%) than that with protective titres against MenA (87.5%), W (78.1%), and Y (87.5%). CONCLUSIONS: Immune responses against MenB in our cohort of people living with HIV at 2.5 years of follow-up were reassuring, with 68.8% of participants retaining protection against all three reference strains. However, responses against MenC were lower than those against MenA, W, and Y serogroups.

Omicron BA.1-containing mRNA-1273 boosters compared with the original COVID-19 vaccine in the UK: a randomised, observer-blind, active-controlled trial.

BACKGROUND: The omicron BA.1 bivalent booster is used globally. Previous open-label studies of the omicron BA.1 (Moderna mRNA-1273.214) booster showed superior neutralising antibody responses against omicron BA.1 and other variants compared with the original mRNA-1273 booster. We aimed to compare the safety and immunogenicity of omicron BA.1 monovalent and bivalent boosters with the original mRNA-1273 vaccine in a large, randomised controlled trial. METHODS: In this large, randomised, observer-blind, active-controlled, phase 3 trial in the UK (28 hospital and vaccination clinic sites), individuals aged 16 years or older who had previously received two injections of any authorised or approved COVID-19 vaccine, with or without an mRNA vaccine booster (third dose), were randomly allocated (1:1) using interactive response technology to receive 50 µg omicron BA.1 monovalent or bivalent vaccines or 50 µg mRNA-1273 administered as boosters via deltoid intramuscular injection. The primary outcomes were safety and immunogenicity at day 29, including prespecified non-inferiority and superiority of booster immune responses, based on the neutralising antibody geometric mean concentration (GMC) ratios of the monovalent and bivalent boosters compared with mRNA-1273. Safety was assessed in all participants who received first or second boosters, and primary immunogenicity outcomes were assessed in all participants who received the planned booster dose, had pre-booster and day 29 antibody data, had no major protocol deviations, and who were SARS-CoV-2-negative. The study is registered with EudraCT (2022-000063-51) and ClinicalTrials.gov (NCT05249829) and is ongoing. FINDINGS: Between Feb 16 and March 24, 2022, 724 participants were randomly allocated to receive omicron BA.1 monovalent (n=366) or mRNA-1273 (n=357), and between April 2 and June 17, 2022, 2824 participants were randomly allocated to receive omicron BA.1 bivalent (n=1418) or mRNA-1273 (n=1395) vaccines as second boosters. Median durations (months) between the most recent COVID-19 vaccine and study boosters were similar for omicron BA.1 monovalent (4·0 months [IQR 3·6-4·7]) and mRNA-1273 (4·1 [3·5-4·7]), and for the omicron BA.1 bivalent (5·5 [4·8-6·2]) and mRNA-1273 (5·4 [4·8-6·2]) boosters. The omicron BA.1 monovalent and bivalent boosters elicited superior neutralising GMCs against the omicron BA.1 variant compared with mRNA-1273, with GMC ratios of 1·68 (99% CI 1·45-1·95) and 1·53 (1·41-1·67) at day 29 post-booster doses in participants without previous SARS-CoV-2 infection. Both boosters induced non-inferior ancestral SARS-CoV-2 (Asp614Gly) immune responses with GMCs that were similar for the bivalent (2987·2 [95% CI 2814·9-3169·9]) versus mRNA-1273 (2911·3 [2750·9-3081·0]) and lower for the monovalent (2699·7 [2431·3-2997·7] vs 3020·6 [2776·5-3286·2]) boosters, with respective GMC ratios of 1·05 (99% CI 0·96-1·15) and 0·82 (95% CI 0·74-0·91). Results were comparable regardless of previous SARS-CoV-2 infection status. Incidences of solicited adverse reactions with the omicron BA.1 monovalent (335 [91·3%] of 367 participants) and omicron BA.1 bivalent (1285 [90·4%] of 1421 participants) boosters were similar to those observed previously for mRNA-1273, with no new safety concerns identified and no occurrences of fatal adverse events. INTERPRETATION: Omicron-containing booster vaccines generated superior immunogenicity against omicron BA.1 and comparable immunogenicity against the original strain with no new safety concerns. It remains important to continuously monitor the immune responses and real-world vaccine effectiveness as divergent SARS-CoV-2 variants emerge. FUNDING: Moderna.

Safety and Efficacy of the NVX-CoV2373 Coronavirus Disease 2019 Vaccine at Completion of the Placebo-Controlled Phase of a Randomized Controlled Trial.

BACKGROUND: The recombinant protein-based vaccine, NVX-CoV2373, demonstrated 89.7% efficacy against coronavirus disease 2019 (COVID-19) in a phase 3, randomized, observer-blinded, placebo-controlled trial in the United Kingdom. The protocol was amended to include a blinded crossover. Data to the end of the placebo-controlled phase are reported. METHODS: Adults aged 18-84 years received 2 doses of NVX-CoV2373 or placebo (1:1) and were monitored for virologically confirmed mild, moderate, or severe COVID-19 (onset from 7 days after second vaccination). Participants who developed immunoglobulin G (IgG) against nucleocapsid protein but did not show symptomatic COVID-19 were considered asymptomatic. Secondary outcomes included anti-spike (S) IgG responses, wild-type virus neutralization, and T-cell responses. RESULTS: Of 15 185 participants, 13 989 remained in the per-protocol efficacy population (6989 NVX-CoV2373, 7000 placebo). At a maximum of 7.5 months (median, 4.5) postvaccination, there were 24 cases of COVID-19 among NVX-CoV2373 recipients and 134 cases among placebo recipients, a vaccine efficacy of 82.7% (95% confidence interval [CI], 73.3%-88.8%). Vaccine efficacy was 100% (95% CI, 17.9%-100.0%) against severe disease and 76.3% (95% CI, 57.4%-86.8%) against asymptomatic disease. High anti-S and neutralization responses to vaccination were evident, together with S-protein-specific induction of interferon-γ secretion in peripheral blood T cells. Incidence of serious adverse events and adverse events of special interest were similar between groups. CONCLUSIONS: A 2-dose regimen of NVX-CoV2373 conferred a high level of ongoing protection against asymptomatic, symptomatic, and severe COVID-19 through >6 months postvaccination. A gradual decrease of protection suggests that a booster may be indicated. CLINICAL TRIALS REGISTRATION: EudraCT, 2020-004123-16.

Comparing reactogenicity of COVID-19 vaccines: a systematic review and meta-analysis.

OBJECTIVES: A number of vaccines have now been developed against COVID-19. Differences in reactogenicity and safety profiles according to the vaccine technologies employed are becoming apparent from clinical trials. METHODS: Five databases (Medline, EMBASE, Science Citation Index, Cochrane Central Register of Controlled Trials, London School of Hygiene and Tropical Medicine COVID-19 vaccine tracker) were searched for relevant randomized controlled trials between 1 January 2020 and 12 January 2022 according to predetermined criteria with no language limitations. RESULTS: Forty-two datasets were identified, with 20 vaccines using four different technologies (viral vector, inactivated, mRNA and protein sub-unit). Adults and adolescents over 12 years were included. Control groups used saline placebos, adjuvants, and comparator vaccines. The most consistently reported solicited adverse events were fever, fatigue, headache, pain at injection site, redness, and swelling. Both doses of mRNA vaccines, the second dose of protein subunit and the first dose of adenovirus vectored vaccines were the most reactogenic, while the inactivated vaccines were the least reactogenic. CONCLUSIONS: The different COVID-19 vaccines currently available appear to have distinct reactogenicity profiles, dependent on the vaccine technology employed. Awareness of these differences may allow targeted recommendations for specific populations. Greater standardization of methods for adverse event reporting will aid future research in this field.

Safety and Efficacy of NVX-CoV2373 Covid-19 Vaccine.

BACKGROUND: Early clinical data from studies of the NVX-CoV2373 vaccine (Novavax), a recombinant nanoparticle vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that contains the full-length spike glycoprotein of the prototype strain plus Matrix-M adjuvant, showed that the vaccine was safe and associated with a robust immune response in healthy adult participants. Additional data were needed regarding the efficacy, immunogenicity, and safety of this vaccine in a larger population. METHODS: In this phase 3, randomized, observer-blinded, placebo-controlled trial conducted at 33 sites in the United Kingdom, we assigned adults between the ages of 18 and 84 years in a 1:1 ratio to receive two intramuscular 5-µg doses of NVX-CoV2373 or placebo administered 21 days apart. The primary efficacy end point was virologically confirmed mild, moderate, or severe SARS-CoV-2 infection with an onset at least 7 days after the second injection in participants who were serologically negative at baseline. RESULTS: A total of 15,187 participants underwent randomization, and 14,039 were included in the per-protocol efficacy population. Of the participants, 27.9% were 65 years of age or older, and 44.6% had coexisting illnesses. Infections were reported in 10 participants in the vaccine group and in 96 in the placebo group, with a symptom onset of at least 7 days after the second injection, for a vaccine efficacy of 89.7% (95% confidence interval [CI], 80.2 to 94.6). No hospitalizations or deaths were reported among the 10 cases in the vaccine group. Five cases of severe infection were reported, all of which were in the placebo group. A post hoc analysis showed an efficacy of 86.3% (95% CI, 71.3 to 93.5) against the B.1.1.7 (or alpha) variant and 96.4% (95% CI, 73.8 to 99.5) against non-B.1.1.7 variants. Reactogenicity was generally mild and transient. The incidence of serious adverse events was low and similar in the two groups. CONCLUSIONS: A two-dose regimen of the NVX-CoV2373 vaccine administered to adult participants conferred 89.7% protection against SARS-CoV-2 infection and showed high efficacy against the B.1.1.7 variant. (Funded by Novavax; EudraCT number, 2020-004123-16.).