TABLE 3.

Vaccine effectiveness against A(H3N2).

	Controls a		Cases a		VE b with population age weighting (95% CI)
	Unvacc	Vacc	Unvacc	Vacc
A(H3N2), all cases	2377	1395	551	154	50% (37%–61%)
A(H3N2), cases with genetic characterisation	2377	1395	288	72	54% (37%–66%)
Subclade 2a.1b	2377	1395	77	16	69% (45%–83%)
Subclade 2a.3a.1	2377	1395	42	5	69% (24%–87%)
Subclade 2b	2377	1395	136	37	50% (23%–67%)

Abbreviations: CI = confidence interval, unvacc = unvaccinated, vacc = vaccinated.

^a Cell counts include those with missing data for onset (all in this analysis have known vaccination date).

^b Adjustments were made for week of sample (spline), age group, scheme and clinical risk status.