2023-24 COVID-19 Vaccine Significantly Protected Against COVID-19 Visits, Stays

US adults who did not receive the BNT162b2 XBB vaccine (Pfizer-BioNTech’s 2023-2024 formulation) but had received older versions of COVID-19 vaccines had little, if any, added protection against COVID-19 hospitalizations and ambulatory visits compared with adults who never received a COVID-19 vaccine, according to study results published online ahead of print in JAMA Internal Medicine.

“Receipt of a BNT162b2 XBB vaccine, however, was associated with statistically significant reduced risk of developing a range of COVID-19 outcomes during the early part of the 2023 to 2024 viral respiratory season—with the strongest protective effects seen against hospital admission,” wrote corresponding author Sara Y. Tartof, PhD, MPH, of Kaiser Permanente Southern California, Pasadena, California, and study coauthors.

The case-control study included 2854 cases and 15 345 controls from the Kaiser Permanente Southern California health system. Researchers estimated the effectiveness of the BNT162b2 XBB vaccine against COVID-19–associated hospitalization and emergency department/urgent care visits between October 10, 2023, and December 10, 2023.

According to the study, the adjusted estimated effectiveness of the BNT162b2 XBB vaccine, administered a median 34 days earlier, was 62% against COVID-19 hospitalization and 58% against COVID-19 emergency department/urgent care visits compared with not having received an XBB vaccine. Researchers found no statistically significant reduced risk of COVID-19 hospitalization and emergency department/urgent care visits for adults without the BNT162b2 XBB vaccine but who had received older versions of COVID-19 vaccines compared with adults who never received a COVID-19 vaccine.

In secondary analyses, the BNT162b2 XBB vaccine provided similar protection in adults regardless of age group and the number of prior COVID-19 vaccine doses received, the study showed.

“These findings reaffirm current recommendations for broad age-based use of annually updated COVID-19 vaccines,” researchers advised.

Reference

Tartof SY, Slezak JM, Frankland TB, et al. Estimated effectiveness of the BNT162b2 XBB vaccine against COVID-19. JAMA Intern Med. Published online June 24, 2024. doi:10.1001/jamainternmed.2024.1640