Chart S1. Search strategies used for databases searched.

Database	Search Strategy
PubMed	(“COVID-19*” OR “COVID 19*” OR COVID19* OR COVID-19 [mh] OR “2019-nCoV*” OR “2019 nCoV*” OR SARS* OR Coronavirus*) AND (vaccine OR vaccines OR immunization OR immunizations) AND (pregnancy OR pregnancies OR gestation)
Embase	(“COVID-19*” OR “COVID 19*” OR “COVID19* OR COVID-19 OR “2019-nCoV*” OR “2019 nCoV*” OR SARS* OR Coronavirus*) AND (vaccine OR vaccines OR immunization OR immunizations) AND (pregnancy OR pregnancies OR gestation)
Cochrane Central	(“COVID-19*” OR “COVID 19*” OR “COVID19* OR COVID-19 OR “2019-nCoV*” OR “2019 nCoV*” OR SARS* OR Coronavirus*) AND (vaccine OR vaccines OR immunization OR immunizations) AND (pregnancy OR pregnancies OR gestation)