Table 2.

Adjusted vaccine effectiveness of the BNT162b2 XBB vaccine for hospitalization, ED/UC visits, and outpatient visits by variant period and time since vaccination

Outcome	Likely XBB (Sep 25 – Nov 30, 2023)		Likely JN.1 (Jan 1 – Jan 31, 2024)
	VE (95% CI) by days since receipt of XBB dose
	≤ 60	61–133	≤ 60	61–133
Hospitalization	62 (44–74)	–*	32 (3–52)	37 (19–51)
ED/UC visit	52 (37–63)	–*	41 (23–54)	30 (16–41)
Outpatient visit	50 (25–66)	–*	31 (1–52)	20 (-4–38)

CI= confidence interval; ED/UC= emergency department/urgent care; VE= vaccine effectiveness

Compared the odds of receiving a BNT162b2 XBB vaccine between SARS-CoV-2 positive cases and SARS-CoV-2 negative controls by days since vaccination. Adjusted for the week of ARI episode, age, sex, race, ethnicity, BMI category, Charlson Comorbidity Index, receipt of 2023-2024 influenza vaccine, receipt of pneumococcal vaccine in the past 5 years, interactions with healthcare systems in the year prior, previous SARS-CoV-2 infection, smoking status, immunocompromised status, and Census region.

*VE estimates based on 2 × 2 comparison tables with a cell size <5 were not reported due to imprecision.