New BNT162b2 XBB Vaccine Provides Significant Additional Protection Against COVID-19 Hospitalization and ED Visits: Study
Researchers have found that the recently recommended BNT162b2 XBB vaccine (Pfizer-BioNTech; 2023-2024 formulation) offers substantial additional protection against COVID-19-associated hospitalization and emergency department (ED) or urgent care (UC) visits in US adults. This test-negative case-control study, conducted within the Kaiser Permanente Southern California health system, provides early data on the effectiveness of the new XBB vaccine. The study was conducted by Sara Y. Tartof and colleagues and was published in JAMA Internal Medicine.
With the ongoing evolution of SARS-CoV-2, updated vaccines are essential to maintain effective protection against COVID-19. The BNT162b2 XBB vaccine, formulated for the 2023-2024 season, aims to address the current variants circulating in the population. Previous COVID-19 vaccines have shown decreasing efficacy over time, necessitating updated formulations. This study evaluates the early impact of the BNT162b2 XBB vaccine on preventing severe COVID-19 outcomes.
This study included adults aged 18 and older presenting with acute respiratory illness between October 10, 2023, and December 10, 2023. Cases were identified as those with a positive SARS-CoV-2 polymerase chain reaction test, while controls had an acute respiratory illness but tested negative for SARS-CoV-2. The primary exposure was receipt of the BNT162b2 XBB vaccine compared to not receiving an XBB vaccine of any kind. The effectiveness of older COVID-19 vaccines was also assessed.
The primary outcomes were COVID-19-associated hospitalizations and ED/UC encounters. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using multivariable logistic regression models adjusted for demographic and clinical characteristics. Vaccine effectiveness was estimated as 1 - OR × 100%.
Among 2,854 cases and 15,345 controls (median [IQR] age, 56 [37-72] years; 10,658 [58.6%] female), the BNT162b2 XBB vaccine showed significant effectiveness.
The adjusted effectiveness of the XBB vaccine, received a median of 34 days prior, was 62% (95% CI, 32%-79%) against COVID-19 hospitalization and 58% (95% CI, 48%-67%) for ED/UC visits.
In contrast, those who had received only older versions of COVID-19 vaccines did not exhibit statistically significant protection against severe outcomes.
Hospitalization: BNT162b2 XBB vaccine was 62% effective (95% CI, 32%-79%).
ED/UC Visits: BNT162b2 XBB vaccine was 58% effective (95% CI, 48%-67%).
Older Vaccines: No significant protection against hospital admission was observed.
The study highlights the importance of the updated BNT162b2 XBB vaccine in providing additional protection against COVID-19 outcomes. The lack of significant protection from older vaccines underscores the necessity for annual updates to match the evolving virus. The results support broad age-based recommendations for the new XBB vaccine to enhance population immunity and reduce severe cases.
Findings from this case-control study reaffirm current recommendations for the annual use of updated COVID-19 vaccines. The BNT162b2 XBB vaccine provides significant additional protection against hospitalization and ED/UC visits, whereas older vaccines offer minimal long-term protection. These results emphasize the need for continued vaccination efforts with updated formulations to effectively combat COVID-19.
Reference:
Tartof, S. Y., Slezak, J. M., Frankland, T. B., Puzniak, L., Hong, V., Ackerson, B. K., Stern, J. A., Zamparo, J., Simmons, S., Jodar, L., & McLaughlin, J. M. (2024). Estimated effectiveness of the BNT162b2 XBB vaccine against COVID-19. JAMA Internal Medicine. https://doi.org/10.1001/jamainternmed.2024.1640
