Table 3.

Efficacy and effectiveness of COVID-19 vaccine primary series against symptomatic infection and severe outcomes by variant in children

Vaccine type	Vaccine efficacy and effectiveness
	<12 years (except where specified 3–17 years)	12–17 years
Moderna (mRNA)	Omicron efficacy against Symptomatic infection: 55% (6 months to <2 years) and 38% (2–6 years)48 Omicron effectiveness against Any infection: 18% (3–17 years)52	Pre-Omicron efficacy against Symptomatic infection: 93% (12–17 years)114
Pfizer-BioNTech (mRNA)	Pre-Omicron: efficacy against Symptomatic infection: 91% (5 to <12 years)115 Delta and Omicron effectiveness against Any infection 0–13 days post-vaccination: 65% (5–11 years)116 Any infection 28–34 days post-vaccination: 12% (5–11 years)116 Hospitalisation 14–67 days post-vaccination: 74% (5–11 years)117 MIS-C: 94% in Denmark (5–17 years)25 Omicron effectiveness against Any infection 0–14 days post-vaccination: 39% (5–11 years)118 Any infection 43–84 days post-vaccination: 21% (5–11 years)118 Any infection: 28% (3–17 years)52 Symptomatic infection 2 months post-vaccination: 29% (5–11 years)119 Symptomatic infection: 80.4% (6 months–4 years)47	Alpha and Delta efficacy against Symptomatic infection: 100% (12–15 years)120 Delta effectiveness against Symptomatic infection 7–21 days post-vaccination: 93% (12–18 years)121 Symptomatic infection 14–27 days post-vaccination: 86% in Brazil and 91% in Scotland (12–17 years)122 Hospitalisation: 94% (12–18 years)123 MIS-C: 91% in France and USA (12–18 years)24 26 Delta and Omicron effectiveness against Any infection 0–13 days post-vaccination: 76% (12–17 years)116; 80% (16–17 years) and 79% (12–15 years)124 Any infection 14–29 days post-vaccination: 83% (16–17 years) and 77% (12–15 years)124 Any infection 28–34 days post-vaccination: 56% (12–17 years)116 Any infection 30–59 days post-vaccination: 61% (16–17 years) and 50% (12–15 years)124 Hospitalisation 14–149 days post-vaccination: 92% (12–15 years) and 94% (16–17 years)117 Omicron effectiveness against Symptomatic infection 14–27 days post-vaccination: 63% in Brazil and 78% in Scotland (12–17 years)122 Symptomatic infection 7–34 days post-vaccination: 53% (16–17 years)125 Symptomatic infection ≥63 days post-vaccination: 23% (16–17 years)125 Symptomatic infection 2 months post-vaccination: 17% (12–15 years)119 Symptomatic infection ≥98 days post-vaccination: 14% in Brazil and 31% in Scotland (12–17 years)122 Hospitalisation: 81% (12–17 years)126 Hospitalisation or death ≥98 days post-vaccination: 85% (12–17 years)122
Novavax (protein subunit)		Delta efficacy against Symptomatic infection: 80% (12–17 years)127
Sinovac (inactivated virus)	Delta and Omicron effectiveness against Symptomatic infection: 76% (6–11 years)128 Hospitalisation: 78% (6–11 years)128 Omicron effectiveness against Symptomatic infection: 40% (6–11 years)50 Hospitalisation: 59% (6–11 years)50 Any infection: 38% (3–5 years)51 Hospitalisation: 65% (3–5 years)51
Sinopharm (inactivated virus)	Omicron effectiveness against Any infection: 28% (3–17 years)52
AstraZeneca (viral vector)	Trials suspended when evidence emerged of the higher risk of thrombosis with thrombocytopaenia syndrome in adults

MIS-C, multisystem inflammatory syndrome in children.