Safety of a second homologous Ad26.COV2.S vaccine among healthcare workers in the phase 3b implementation Sisonke study in South Africa.

The Sisonke 2 study provided a homologous boost at least 6 months after administration of the priming dose of Ad26.COV2.S for healthcare workers enrolled on the Sisonke phase 3b implementation study. Safety monitoring was via five reporting sources: (i.) self-report through a web-link; (ii.) paper-based case report forms; (iii.) a toll-free telephonic reporting line; (iv.) healthcare professionals-initiated reports; and (v.) active linkage with National Disease Databases. A total of 2350 adverse events were reported by 2117 of the 240 888 (0.88%) participants enrolled; 1625 of the 2350 reported events are reactogenicity events and 28 adverse events met seriousness criteria. No cases of thrombosis with thrombocytopaenia syndrome were reported; all adverse events including thromboembolic disorders occurred at a rate below the expected population rates apart from one case of Guillain Barre Syndrome and one case of portal vein thrombosis. The Sisonke 2 study demonstrates that two doses of Ad26.COV2.S is safe and well tolerated; and provides a feasible model for national pharmacovigilance strategies for low- and middle-income settings.

Mosaic HIV-1 vaccine regimen in southern African women (Imbokodo/HVTN 705/HPX2008): a randomised, double-blind, placebo-controlled, phase 2b trial.

BACKGROUND: HIV type 1 (HIV-1) remains a global health concern, with the greatest burden in sub-Saharan Africa. Despite 40 years of research, no vaccine candidate has shown durable and protective efficacy against HIV-1 acquisition. Although pre-exposure prophylaxis in groups with high vulnerability can be very effective, barriers to its use, such as perceived low acquisition risk, fear of stigma, and concerns about side-effects, remain. Thus, a population-based approach, such as an HIV-1 vaccine, is needed. The current study aimed to evaluate the efficacy and safety of a heterologous HIV-1 vaccine regimen, consisting of a tetravalent mosaic adenovirus 26-based vaccine (Ad26.Mos4.HIV) and aluminium phosphate-adjuvanted clade C glycoprotein (gp) 140, in young women at risk of acquiring HIV-1 in southern Africa. METHODS: This randomised, double-blind, phase 2b study enrolled sexually active women without HIV-1 or HIV-2 aged 18-35 years at 23 clinical research sites in Malawi, Mozambique, South Africa, Zambia, and Zimbabwe. Participants were centrally randomly assigned (1:1) to receive intramuscular injections of vaccine or saline placebo in stratified permuted blocks via an interactive web response system. Study participants, study site personnel (except those with primary responsibility for study vaccine preparation and dispensing), and investigators were masked to treatment group allocation. The vaccine regimen consisted of Ad26.Mos4.HIV administered at months 0 and 3 followed by Ad26.Mos4.HIV administered concurrently with aluminium phosphate-adjuvanted clade C gp140 at months 6 and 12. The primary efficacy outcome was vaccine efficacy in preventing laboratory-confirmed HIV-1 acquisition diagnosed between visits at month 7 and month 24 after the first vaccination (VE[7-24]) in the per-protocol population, which included participants who had not acquired HIV-1 4 weeks after the third vaccination, received all planned vaccinations at the first three vaccination visits within the protocol-specified windows, and had no major protocol deviations that could affect vaccine efficacy. Primary safety outcomes were assessed in randomly assigned participants who received one study injection or more based on the actual injection received. The primary safety endpoints were the incidences of unsolicited adverse events (AEs), solicited local and systemic AEs, serious AEs, AEs of special interest, and AEs leading to discontinuation of vaccination. This trial is registered with ClinicalTrials.gov, NCT03060629, and is complete. FINDINGS: Between Nov 3, 2017, and June 30, 2019, 2654 women were randomly assigned, of whom 2636 women (median age of 23 years [IQR 20-25]) were enrolled and received at least one study injection (1313 assigned vaccine, 1323 placebo; 1317 received vaccine, 1319 placebo). Analysis of the primary efficacy outcome in the per-protocol cohort included 1080 women in the vaccine group and 1108 women in the placebo group; the incidence of HIV-1 acquisition per 100 person-years over months 7-24 after the first vaccination was 3·38 (95% CI 2·54-4·41) in the vaccine group and 3·94 (3·04-5·03) in the placebo group, with an estimated VE(7-24) of 14·10% (95% CI -22·00 to 39·51; p=0·40). There were no serious unsolicited AEs, AEs of special interest, or deaths related to the study vaccine. In the vaccine group, 663 (50·3%) of 1317 participants had grade 1 or 2 solicited local AEs and ten (0·8%) of 1317 participants had grade 3 or 4 solicited local AEs. In the placebo group, 305 (23·1%) of 1319 participants had grade 1 or 2 solicited local AEs and three (0·2%) of 1319 participants had grade 3 or 4 solicited local AEs. 863 (65·5%) of 1317 participants in the vaccine group had grade 1 or 2 solicited systemic AEs and 34 (2·6%) of 1317 participants had grade 3 or 4 solicited systemic AEs. 763 (57·8%) of 1319 participants in the placebo group had grade 1 or 2 solicited systemic AEs and 20 (1·5%) of 1319 participants had grade 3 or 4 solicited systemic AEs. Overall, three (0·2%) of 1317 participants in the vaccine group and three (0·2%) of 1319 participants in the placebo group discontinued vaccination due to an unsolicited AE, and three (0·2%) of 1317 participants in the vaccine group and one (0·1%) of 1319 participants in the placebo group discontinued vaccination due to a solicited AE. INTERPRETATION: The heterologous Ad26.Mos4.HIV and clade C gp140 vaccine regimen was safe and well tolerated but did not show efficacy in preventing HIV-1 acquisition in a population of young women in southern Africa at risk of HIV-1. FUNDING: Division of AIDS at the National Institute of Allergy and Infectious Diseases through the HIV Vaccine Trials Network, Bill & Melinda Gates Foundation, Janssen Vaccines & Prevention, US Army Medical Materiel Development Activity, and Ragon Institute.

Allergic reactions to the Ad26.COV2.S vaccine in South Africa.

Background: The Janssen-Ad26.COV2.S vaccine is authorized for use in several countries, with more than 30 million doses administered. Mild and severe allergic adverse events following immunization (AEFI) have been reported. Objective: We sought to detail allergic reactions reported during the Sisonke phase 3B study in South Africa. Methods: A single dose of the Ad26.COV2.S vaccine was administered to 4,77,234 South African health care workers between February 17 and May 17, 2021. Monitoring of adverse events used a combination of passive reporting and active case finding. Telephonic contact was attempted for all adverse events reported as "allergy." Anaphylaxis adjudication was performed using the Brighton Collaboration and National Institute of Allergy and Infectious Disease case definitions. Results: Only 251 (0.052%) patients reported any allergic-type reaction (<1 in 2000), with 4 cases of adjudicated anaphylaxis (Brighton Collaboration level 1, n = 3) (prevalence of 8.4 per million doses). All anaphylaxis cases had a previous history of drug or vaccine-associated anaphylaxis. Cutaneous allergic reactions were the commonest nonanaphylatic reactions and included self-limiting, transient/localized rashes requiring no health care contact (n = 92) or isolated urticaria and/or angioedema (n = 70; median onset, 48 [interquartile range, 11.5-120] hours postvaccination) that necessitated health care contact (81%), antihistamine (63%), and/or systemic/topical corticosteroid (16%). All immediate (including adjudicated anaphylaxis) and most delayed AEFI (65 of 69) cases resolved completely. Conclusions: Allergic AEFI are rare following a single dose of Ad26.COV, with complete resolution in all cases of anaphylaxis. Although rare, isolated, delayed-onset urticaria and/or angioedema was the commonest allergic AEFI requiring treatment, with nearly half occurring in participants without known atopic disease.