Covid-19 immunity lasts nine months after infection, Hiqa advises

Dr Ryan says that extending the period of presumptive immunity has "widespread positive implications" for Irish people.

The Health Information and Quality Authority (Hiqa) says the duration of presumptive Covid-19 immunity should be increased from six months to nine post-infection.

Hiqa made the recommendation to the National Public Health Emergency Team (Nphet) following a review of 19 large cohort studies of reinfection involving more than 640,000 previously infected people, as well as advice from the Covid-19 expert advisory group.

However, the health watchdog says the potential impact of "new variants on natural immunity is evolving rapidly" and needs to be kept under review.

Dr Máirín Ryan, HIQA’s Deputy CEO and Director of Health Technology Assessment, says that across all studies examined by Hiqa "the risk of SARS-CoV-2 reinfection was consistently low" with no increase infection risk over time.

Dr Ryan says that extending the period of presumptive immunity has "widespread positive implications" for Irish people.

A person who was infected with Covid-19 in the last nine months would be exempt from serial testing, and would also increase the number of people under-50 who only needs one dose of vaccine to be considered fully vaccinated.

The extended immunity will have implications on the policies surrounding the proposed EU's digital green certificate for travelling within the bloc.

Dr Ryan says: "It will be important that any policy changes and the evidence behind them are clearly communicated and consistently applied.”