Vaccine type, immune fitness, and virus variant are all factors that can contribute to breakthrough infections in people who are immunised against COVID-19.


Around the world, we are seeing cases of breakthrough infections occurring in people who have been fully immunised (particularly in the US and UK). A breakthrough infection is where an individual fully vaccinated against COVID-19 tests positive for the disease. But why? Firstly, it takes time for your body to build antibodies after each vaccination and you are not considered fully vaccinated until two weeks after your full course. However, some people are testing positive for the disease even after this period. While concerning, it’s essential to understand that no vaccine is 100 per cent effective. There are three main reasons why breakthrough infections can occur:

It’s important to remember, though, that those who develop breakthrough infections are unlikely to become severely ill from the disease. Learn more about how COVID-19 is improving health care