National Institutes of Health Director Dr. Francis Collins announced that a coronavirus vaccine might need two doses to be fully effective.
“Obviously that’s not our favorite. It would be much better if this could all be done with a single injection,” Collins said.
Generally, for cost reasons, one dose is preferred with any vaccine, and also because people are less likely to show up twice to receive an injection.
Collins said the clinical trials of several experimental vaccines will reveal whether one or two doses will be necessary, bt the end of the next month.
Among all the vaccines that are undergoing trials, Collins is expecting that one or more of the vaccines require two shots in order to get a full immune response.
The US Biomedical Advanced Research and Development Authority (BARDA), a part of the Department of Health and Human Services is conducting research on five different experimental vaccines. Pharmaceutical companies Moderna and AstraZeneca are testing the vaccines on humans. Johnson & Johnson, Sanofi, and Merck are developing a vaccine, but have not yet started clinical trials, according to the World Health Organization.
