Earlier this evening the UK Health Secretary Matt Hancock announced that a new genetic variant of the Covid-19 virus could be responsible for the large upswing of cases in the South East of the UK. What does this mean and should we be worried?
(Later this evening, following the first posting of this blog, there has been more information released about this variant and hence this post has been updated)
What do we know about this new mutation in the Covid-19 virus?
- Readers of his blog may remember I covered the background to Covid-19 mutations in October.
- You may find it helpful to revisit that post in which I discuss how mutations occur and what might be their consequences. Hopefully this will also help make sense of the rest of this post: https://makingsenseofcovid19withs.com/2020/10/13/genetic-mutations-in-the-virus-and-in-humans-do-they-offer-a-way-out/
- The UK has been taking an international lead (as far as I can tell) in monitoring for the appearance of different strains of the virus, by a detailed analysis of their genetic code via The CoVid-19 Genomics UK Consortium (COG-UK)
- COG-UK followed up the minister’s announcement with some more detail
- Is it unusual for new strains to appear?
- Not at all, the development of new strains of a virus is a natural process especially during an epidemic as protracted as this
2. Is it usual for such changes to take over and become the predominant strain in an area?
- Yes, this is not unusual.
- One theory is that the virus mutates as it multiplies in our bodies and one of the changes could make it easier for the virus to multiply
- If this was the case, then this new mutation is the one that is more likely to be transmitted and could rapidly become the predominant strain
3. Could the emergence of a new strain be the explanation of the increasing number of cases?
- This does seem to be a reasonable hypothesis based on what I said above.
- The new strain of the virus might be present in such large numbers of new cases because it is better able to transmit infection.
- I might therefore expect ‘R’ to be higher with this new strain
4. Does this mean the new strain will be more dangerous?
- Not at all.
- There are plenty of examples from coronaviruses in other species where a new strain can cause less severe disease, although there are examples where it can be more serious.
- Most expert virologists believe that there is no connection between how good a virus is at spreading to how severe the infection is.
- So, the individual risk of severe infection is not altered but the numbers who become ill could rise
5. Will this affect the success of vaccines?
- Again, expert opinion is on balance probably not
- As readers will know, vaccines are directed against the spike protein of the virus.
- There are over 4000 mutations previously described in the spike protein
- The variant announced late this evening does contains several mutations including one in the spike protein
- This particular strain (N501Y) though also affects a critical part of the spike protein- the part that allows it to lock onto human cells
- Other previously defined mutations in the spike protein are not thought to affect vaccines’ success.
- Thus, despite the fact that this new variant contains such a mutation, antibodies produced in response to the vaccines hopefully should still neutralise the virus.
- For the moment therefore it is reasonable to assume that the current vaccines will still work but this will be under test
6. Could this increase the chances of someone getting a second infection?
- The reassuring thing about Covid-19 is that since the pandemic started, and there have been very large numbers of mutations reported, the numbers of people who have had a second, new infection with a different strain remain small.
- But we cannot know for sure that the previous infections will confer immunity against this new strain or indeed any future mutation.
- We know for example that with seasonal flu there is limited overlap in immunity between annual strains
7. Is there any good news from this?
- The good news is that we have the surveillance in place with this highly sophisticated genetic analysis that has allowed this strain to be detected.
- Using this information scientists might get data-driven answers to the questions above as opposed to opinions!
Conclusions
- Genuinely I am not personally worried unless there is evidence that vaccine success may be influenced
- My answers to (2) and (3) above do offer an explanation to why we are seeing such an increase in the UK (and might also be the case in other countries of course)
- The case for continuing to be vigilant and practice Covid-19 safe behaviours is reinforced
- The quicker we can get roll out of a population-wide vaccination programme to stop transmission, the less the opportunity for the virus to be around to mutate
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Making sense of CoVid-19 with Silman 