Saturday, 17 October 2020

Reinfection Taken Seriously?

I appreciate that finally there now appears to be some reticence to put Covid-19 'facts' out there, before people are certain of the verity. I am, however, somewhat surprised that it has taken 'government scientists' until now to point to the high liklihood of reinfections with the virus (https://www.theguardian.com/world/2020/oct/17/covid-reinfections-to-be-expected-as-virus-spreads-say-government-scientists ). I'm only surprised because a) they are now drawing parallels with the 4 coronaviruses that cause the common cold, where infection leads to perhaps only 6 months of immunity and b) they were very quick, in the early days of the pandemic, to talk about possible 'herd immunity'. Clearly, there is no 'herd immunity' protection for the common cold (it comes round every year). I have noted in earlier posts that, although it is difficult to validate reinfections (you have to be lucky with testing), there have been suggestions of their existence for quite some time. The scientists now note that immune protection from Sars-Cov-2 seems quite short-lived (perhaps less than 6 months?). They seem very interested in the case of one man from Hong Kong, who was identified as reinfected, whilst passing through London from Spain. His second infection appeared to be asymptomatic. It is unclear (but likely?) whether he was shedding virus and could transmit the infection. If reinfections can be both asymptomatic and infective, this raises problems for both 'test and trace' and 'social isolation' as strategies to deal with the pandemic. I would not, however, base too much on one (perhaps atypical?) case. There have been other suggestions that a reinfection can the worse than the first time round.

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