Why some people might be immune to certain COVID-19 vaccines | Gavi, the Vaccine Alliance https://www.gavi.org/vaccineswork/why-some-people-might-be-immune-certain-covid-19-vaccines?fbclid=IwAR2frdrgNRiGkz77k3-gooQ86cdrP1jgBtncwo649Vao9nJrTci2MXoevSg