Effectiveness of BNT162b2 BA.4/5 Bivalent mRNA Vaccine Against Symptomatic COVID-19 Among Immunocompetent Individuals Testing at a Large US Retail Pharmacy

• Published in: The Journal of infectious diseases Vol. 229; no. 3; pp. 648 - 659
• Main Authors: Rudolph, Abby E, Khan, Farid L, Shah, Amy, Singh, Tanya G, Wiemken, Timothy L, Puzniak, Laura A, Jodar, Luis, McLaughlin, John M
• Format: Journal Article
• Language: English
• Published: United States Oxford University Press 14-03-2024
• Subjects: Adolescent; Adult; BNT162 Vaccine; Child, Preschool; COVID-19 - epidemiology; COVID-19 - prevention & control; Humans; Major; mRNA Vaccines; Pharmacy; SARS-CoV-2 - genetics; Vaccines, Combined; effectiveness; COVID-19; BA.4/5; SARS-CoV-2; BNT162b2; United States; bivalent; Omicron; test negative; VE
• ISSN: 0022-1899; 1537-6613; 1537-6613
• DOI: 10.1093/infdis/jiad474

Abstract
Background
Data on the effectiveness of BA.4/5 bivalent vaccine stratified by age and prior infection are lacking.
Methods
This test-negative study used data from individuals ≥5 years of age testing for SARS-CoV-2 with symptoms (15 September 2022 to 31 January 2023) at a large national retail pharmacy chain. The exposure was receipt of 2–4 wild-type doses and a BNT162b2 BA.4/5 bivalent vaccine (>2 months since last wild-type dose). The outcome was a positive SARS-CoV-2 test. Absolute (vs unvaccinated) and relative (vs 2–4 wild-type doses) vaccine effectiveness (VE) were calculated as (1 − adjusted odds ratio from logistic regression) × 100. VE was stratified by age and self-reported prior infection.
Results
Overall, 307 885 SARS-CoV-2 tests were included (7916 aged 5–11, 16 329 aged 12–17, and 283 640 aged ≥18 years). SARS-CoV-2 positivity was 39%; 21% were unvaccinated, 70% received 2–4 wild-type doses with no bivalent vaccine, and 9% received a BNT162b2 BA.4/5 bivalent dose. At a median of 1–2 months after BNT162b2 BA.4/5 bivalent vaccination, depending on age group, absolute VE was 22%–60% and was significantly higher among those reporting prior infection (range, 55%–79%) than not (range, no protection to 50%). Relative VE was 31%–64%.
Conclusions
BNT162b2 BA.4/5 bivalent showed early additional protection against Omicron-related symptomatic COVID-19, with hybrid immunity offering greater protection.
The BNT162b2 BA.4/5 bivalent vaccine provided early additional protection against Omicron-related symptomatic COVID-19 among immunocompetent individuals aged ≥5 years when BA.4/5 and XBB-related sublineages were circulating. In general, effectiveness was highest among those self-reporting prior SARS-CoV-2 infection.