1. currently receiving immunosuppressive medication or anti-cancer chemotherapy. 2. known hiv infection. 3. congenital immune deficiency syndrome. 4. received immunoglobulin or other blood products in the three months prior to potential study booster vaccination. 5. study staff and their relatives. 6. have a history of a severe allergic reaction to any covid-19 vaccines or have a medical exemption to receiving further covid-19 vaccines. 7. cannot read or understand english.

1. currently receiving immunosuppressive medication or anti-cancer chemotherapy. 2. known hiv infection. 3. congenital immune deficiency syndrome. 4. received immunoglobulin or other blood products in the three months prior to potential study booster vaccination. 5. study staff and their relatives. 6. have a history of a severe allergic reaction to any covid-19 vaccines or have a medical exemption to receiving further covid-19 vaccines. 7. cannot read or understand english.

currently receiving immunosuppressive medication or anti-cancer chemotherapy. known hiv infection. congenital immune deficiency syndrome. received immunoglobulin or other blood products in the three months prior to potential study booster vaccination. study staff and their relatives. have a history of a severe allergic reaction to any covid-19 vaccines or have a medical exemption to receiving further covid-19 vaccines. cannot read or understand english.

currently receiving immunosuppressive medication or anti-cancer chemotherapy. known hiv infection. congenital immune deficiency syndrome. received immunoglobulin or other blood products in the three months prior to potential study booster vaccination. study staff and their relatives. have a history of a severe allergic reaction to any covid-19 vaccines or have a medical exemption to receiving further covid-19 vaccines. cannot read or understand english.