Infectious Disease Daily Report: 01/25/024

COVID-19 Vaccination

A phase 3b implementation study investigated the effect of a second homologous Ad26.COV2.S vaccine in 240,888 healthcare workers in South Africa and found 2350 adverse events reported by 2117 participants (0.88%), with 1625 being reactogenicity events and 28 meeting seriousness criteria (1). No cases of thrombosis with thrombocytopaenia syndrome were reported, demonstrating the vaccine's safety and tolerability.

Reference

Takalani A, Robinson M, Jonas P, Bodenstein A, Sambo V, Jacobson B, Louw V, Opie J, Peter J, Rowji P, Seocharan I, Reddy T, Yende-Zuma N, Khutho K, Sanne I, Bekker LG, Gray G, Garrett N, Goga A; Sisonke Study Team. Safety of a second homologous Ad26.COV2.S vaccine among healthcare workers in the phase 3b implementation Sisonke study in South Africa. Vaccine. 2024 Jan 25:S0264-410X(24)00078-1. doi: 10.1016/j.vaccine.2024.01.066. Epub ahead of print. PMID: 38278629.

Typhoid Fever

A phase 3, double-blind, randomised controlled trial study investigated the effect of Vi polysaccharide conjugated to tetanus toxoid vaccine (Vi-TT) in 28,130 children with no previous history of typhoid vaccination in Blantyre, Malawi and found efficacy of Vi-TT was 78.3% with 163 children needed to be vaccinated to prevent one case (1). Efficacies by age group varied, showing durability for at least 4 years among children aged 9 months to 12 years.

Reference

Patel PD, Liang Y, Meiring JE, Chasweka N, Patel P, Misiri T, Mwakiseghile F, Wachepa R, Banda HC, Shumba F, Kawalazira G, Dube Q, Nampota-Nkomba N, Nyirenda OM, Girmay T, Datta S, Jamka LP, Tracy JK, Laurens MB, Heyderman RS, Neuzil KM, Gordon MA; TyVAC team. Efficacy of typhoid conjugate vaccine: final analysis of a 4-year, phase 3, randomised controlled trial in Malawian children. Lancet. 2024 Jan 25:S0140-6736(23)02031-7. doi: 10.1016/S0140-6736(23)02031-7. Epub ahead of print. PMID: 38281499.

Influenza vaccine response in pediatric hematopoietic cell transplant recipients

A phase II multi-center, double-blinded, randomized controlled trial compared the durability of antibody responses of two doses of high-dose trivalent influenza vaccine (HD-TIV) versus two doses of standard-dose quadrivalent influenza vaccine (SD-QIV) in 170 pediatric allogeneic hematopoietic cell transplant (HCT) recipients aged 3-17 years old who were 3-35 months post-allogeneic HCT (1). The study found that HD-TIV administered ≥6 months post-HCT was associated with higher geometric mean titer ratios (aGMR) compared to the early post-HCT period, indicating that two doses of HD-TIV were more immunogenic than SD-QIV, especially when administered later post-HCT.

Reference

Schuster JE, Hamdan L, Dulek DE, Kitko CL, Batarseh E, Haddadin Z, Stewart LS, Stahl A, Potter M, Rahman H, Kalams SA, Bocchini CE, Moulton EA, Coffin SE, Ardura MI, Wattier RL, Maron G, Grimley M, Paulsen G, Harrison CJ, Freedman JL, Carpenter PA, Englund JA, Munoz FM, Danziger-Isakov L, Spieker AJ, Halasa NB; Pediatric HCT Flu Study. The Durability of Antibody Responses of Two Doses of High-Dose Relative to Two Doses of Standard-Dose Inactivated Influenza Vaccine in Pediatric Hematopoietic Cell Transplant Recipients: A Multi-Center Randomized Controlled Trial. Clin Infect Dis. 2024 Jan 25;78(1):217-226. doi: 10.1093/cid/ciad534. PMID: 37800415; PMCID: PMC10810702.