The Journal of Infectious Diseases yesterday issued a press release highlighting a report they had accepted for publication. In that report a young Hong Kong male who had definite but mild Covid-19 in March, was tested positive 10 days ago for a different strain of the virus-the first such case globally. The Hong Kong scientists suggested this should cause concern about immunity following infection, although other scientists have been reassuring. What issues does this report raise?
A note about the public release of this report
- The full scientific report is not, at the time of writing, available on the Journal’s website, so the details cannot be explored
- This is not acceptable: if reports are going to be released to the public, then the full report must be available for scrutiny.
- Note that in CNN’s news bar they falsely mentioned the case was a woman!
What is the significance of a single case report?
- There have been 24 million cases of Covid-19 documented worldwide.
- There have been cases suggesting people being ill twice but this is the first to show definitely a new infection.
- Of course, other second cases may have arisen and not identified, but if there had been a significant number we would know.
- The fact that this is the first is reassuring.
Should we worry that the second infection was a different strain?
- There are new strains of the virus emerging all the time.
- As said before in this blog, that is normal for a virus but interestingly Covid-19 shows less tendency to mutate than other viruses
- If it hadn’t been a separate strain, identified by more stringent genetic testing than is usually done, then it would not have been possible definitively to say this was a new infection
Does this case prove that immunity from a first infection would not protect against a different strain?
- It is already well known (and discussed in this blog on 28 July) that immunity can fall over time especially in cases of mild infection
- What is not known is whether, despite falling immunity, when faced with a new infection, the body’s antibody and other immune protection mechanisms would still come into play
- For sure, the more different the second strain of a virus, the greater the possibility that the existing immunity might not full give protection
- BUT the antibody response may still give some protection across strains
The Hong Kong case is interesting because….
- The young man had no symptoms the second time
- Although he was positive on swab testing the second time confirming the presence of the virus, he may have had an antibody response which protected him from any serious consequences
- Thus (and not wishing to make conclusions on one case) perhaps it is reassuring that he did not become ill
Any issues about vaccines?
- Not really, as the vaccines are designed to be active against the spike protein
- There is no evidence yet that the spike proteins vary in different strains
Conclusion
- Nothing is certain about this virus (perhaps justifying this blog!!!)
- However, the case should not have received the publicity it did.
Making sense of CoVid-19 with Silman 