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Covid-19: Past infection provides 83% protection for five months but may not stop transmission, study finds

BMJ 2021; 372 doi: (Published 14 January 2021) Cite this as: BMJ 2021;372:n124

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  1. Elisabeth Mahase
  1. The BMJ

People who have previously been infected with covid-19 are likely to be protected against reinfection for several months, but could still carry the virus in their nose and throat and transmit it to others, according to a study which regularly tested thousands of healthcare workers.1

The preprint reported interim results from Public Health England’s Siren study between 18 June and 24 November 2020. During that period, researchers detected 44 potential reinfections and 409 new infections. This equated to an 83% rate of protection from reinfection, which appeared to last for at least for five months from first becoming sick.

The research team warned, however, …

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