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expert reaction to study presenting genomic evidence for a case of re-infection with COVID-19 in the US

A study, published in the Lancet Infectious Diseases, looked at genomic evidence for a case of re-infection with COVID-19 in the US.


Prof Brendan Wren, Professor of Vaccinology, London School of Hygiene & Tropical Medicine, said:

“The study shows a rare example of re-infection by the SARS-CoV-2 verified by genome sequencing and is the fifth confirmed case of re-infection.  The demonstration that it is possible to be re-infected by SARS-CoV-2 may suggest that a Covid-19 vaccine may not be totally protective.  However, given the 40+ million cases worldwide these small examples of re-infection are tiny and should not deter efforts to develop vaccines.”


Dr Simon Clarke, Associate Professor of Cellular Microbiology at the University of Reading, said:

“The possibility of re-infection with the coronavirus has been something that medical science has been waiting to answer.  Initial over-confident predictions that once you’d had it, you couldn’t get it again, were opinions rather than facts.  It is becoming increasingly clear that re-infections are possible, but we can’t yet know how common this will be.  It might prove to be a rare phenomenon, but it’s equally possible that these could be the first few cases and that there are many more to come.

“The implications of more widespread reinfection are that herd immunity would not work.  This provides further scientific evidence for extreme caution in proposing policies that allow Covid-19 to rip through the younger population while attempting to shield the elderly and vulnerable – even if that were possible, which it probably isn’t.  If people can be reinfected easily, it could also have implications for vaccination programmes as well as our understanding of when and how the pandemic will end.”


Prof Paul Hunter, Professor in Medicine, UEA, said:

“I think most of us have thought that reinfection with COVID-19 was likely to become common as individuals’ immunity levels declined post infection.  However, the findings in the paper by Tillett and colleagues are very concerning both from the point of view of the very short time between the two infections and the fact that the second illness was more severe than the first.  Until this and one other recent report from Ecuador I for one assumed that any second infection was likely after only a few months and then most likely to be less severe, at least in otherwise immune competent individuals.  Indeed, apart from this US and the Ecuadorian cases, other reports of reinfection have tended to be asymptomatic.

“Given the fact that to date over 37 million people have had the infection we would have expected to have heard of many more incidents if such very early reinfections with severe illness were common.  Nevertheless, repeat infections do occur with different strains and I suspect many more will be found over coming months as immunity declines in individuals after infection.  It is too early to say how common increased severity of illness associated with a second infection will be. I t is likely that the risk of more severe disease during a re-infection will be overestimated from published data as mild and asymptomatic individuals are much less likely to be screened than repeat symptomatic cases.

“It is too early to say for certain what the implications of these findings are for any immunization programme.  But these findings reinforce the point that we still do not know enough about the immune response to this infection.  We need to study such reinfections with severe illness in order to identify whether there are specific genetic or other factors that could explain the risk of severe disease and then hopefully prevent or reduce the severity of any infection.”


‘Genomic evidence for reinfection with SARS-CoV-2: a case study’ by Richard L Tillett et al. was published in the Lancet Infectious Diseases at 23:30 UK time on Monday 12 October 2020.

DOI: 10.1016/S1473-3099(20)30764-7


Declared interests

None received.

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