Immunity post-COVID lasts six months

HIQA advises NPHET after evidence review
  • Deborah Condon

The duration of immunity following infection with COVID-19 should be taken to be six months, the Health Information and Quality Authority (HIQA) has said.

The current guidance in Ireland is that immunity following infection with the virus lasts for at least 12 weeks. However, HIQA has now published its advice to the National Public Health Emergency Team (NPHET) on the duration of immunity following infection.

"We have advised NPHET that presumptive immunity should be extended to six months post-infection. The risk of reinfection with SARS-CoV-2 during that period is very low and no evidence was found to suggest that immunity wanes over this period," commented HIQA deputy CEO, Dr Máirín Ryan.

HIQA's advice was informed by international evidence, which included five large cohort studies. Three of these studies involved healthcare workers.

"Our advice has implications for a number of policy areas including exemption from close contact status, serial testing in selected work settings and testing prior to admission or transfer to a healthcare facility," Dr Ryan noted.

However, HIQA acknowledged that the studies it identified were all conducted prior to December 2020. Since then, the vaccine rollout has begun and a number of new variants have been identified. As a result, "the applicability of the findings to the new strains and vaccinated populations is unknown", HIQA said.

It also cautioned that the advice may not apply to some groups, including the elderly and those who are immunocompromised.

HIQA will continue to review this. The advice it provided to NPHET can be viewed here.


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