大象传媒

There are different policies concerning the wait between the first and second vaccine. Some countries are recommendind a three or four week gap, others twelve, and others are dependent on when supplies of a second vaccine arrives.

Research has been done to assess the optimal delay. Trials looked at leaving a month, a ten-week and even a ten-month gap betwaeen the first and second dose, and the results suggest that the longer the gap, the better the immune response. However, this means that people are exposed to more infection the longer while they wait for their second vaccination, so the decision will depend on the pandemic situation in a country, and how dangerious it is for people to wait. 大象传媒 Science and Health Correspondent James Gallagher explains.

Photo: People being vaccinated in Iztapalapa, Mexico City Credit: Getty Images