Table 2 Effectiveness of CoronaVac against symptomatic and severe COVID-19, among pregnant women aged 18–49 years in Brazil (comparison of symptomatic and severe cases with test-negative controls)

Symptomatic COVID-19

 Unvaccinated

Ref

Ref

Ref

Ref

 One dose < 13 days

0.94 (0.77–1.14)

1.35 (1.10–1.66)

1.35 (1.09–1.68)

–

0.006

 Partially vaccinated (one dose ≥ 14 days)

0.64 (0.53–0.77)

1.00 (0.82–1.22)

0.94 (0.76–1.18)

5.02 (–18.22– 23.69)

0.645

 Two doses ≥ 14 days

0.42 (0.35–0.50)

0.69 (0.57–0.83)

0.59 (0.47–0.72)

40.97 (27.07– 52.22)

< 0.001

Severe COVID-19

 Unvaccinated

Ref

Ref

Ref

Ref

 One dose < 13 days

1.38 (0.87–2.19)

1.64 (1.01–2.65)

1.42 (0.83–2.43)

–

0.192

 Partially vaccinated (one dose ≥ 14 days)

0.30 (0.13–0.69)

0.38 (0.16–0.87)

0.32 (0.13–0.80)

67.74 (20.00–87.00)

0.015

 Two doses ≥ 14 days

0.15 (0.06–0.37)

0.20 (0.08–0.50)

0.14 (0.05–0.40)

85.39 (59.44– 94.80)

< 0.001