New BNT162b2 XBB Vaccine Provides Significant Additional Protection Against COVID-19 Hospitalization and ED Visits: Study

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