doctor holding covid-19 vaccine vial for vaccination tagged with 4th dose

2019ncov 3rd 4rd 4th administer antibodies antigens booster bottle care corona coronavirus cov covid covid19 development disease doctor dose doses drug form fourth generic health healthcare immunity immunization infectious laboratory medical medication mrna new omicron pharmaceutical pharmacology prevention remember report request requisition sarscov2 shot shots strain vaccinating vaccination vaccine vaccines variant variants vial virology virus