With limited supply, the study examined the concept of using vaccines as post-exposure prophylaxis (PEP), meaning people could be vaccinated following exposure to a close contact who tested positive for COVID-19, preventing them from contracting the disease.

“Vaccines are effective as post-exposure prophylaxis for other infections, such as smallpox, hepatitis A and measles, but we’re yet to test whether COVID-19 vaccines would work in the same way,” Professor MacIntyre said. READ MORE