Reasons why Covid variant could kill more people are uncertain

Those who may have been comforted in recent weeks by the evolutionary theory of virus mutation – that the more transmissible they become, the less lethal they are – may now be pondering the news that the variant that originated in Kent not only spreads more easily but may kill more people too.

Britain’s chief scientific adviser, Sir Patrick Vallance, at the Downing Street press briefing, said it could be that in people over 60 with Covid, 13 or 14 might die in every 1000, instead of 10 as has been the case. The reasons still seem to be uncertain.

A summary of rebuttals offered by the Anti-Virus website to selected claims made by sceptics – detailed in full on the site.

Claim: The infection fatality rate (IFR) is very low – 99.5% of people who get it survive
Response: The 0.5% figure has been challenged by significantly higher recent estimates, and it understates how lethal Covid is to older people who get it. The IFR is being kept low by lockdown – and if the virus were allowed to spread, the death rate would be higher because there wouldn't be enough space in hospitals to treat those who need it.

Claim: 91% of Covid ‘cases’ are false positives. This is a ‘casedemic’
Response: This theory is based on a statistical misunderstanding, and since during the summer (when Covid cases were low) only 0.3% of tests were showing positive results, it cannot be that a much greater proportion of positive tests are now “false”. In any case, the huge rises in hospitalisations and deaths disprove the idea that people aren’t really getting sick.

Claim: There are no excess deaths
Response: The ONS recently estimated 14% more deaths in the previous year than the baseline from the previous five years – and that happened even though in the latter part of the year, deaths from causes other than coronavirus actually fell.

Claim: Lockdowns cause more deaths than they prevent
Response: This contradicts all the evidence that virtually all of the excess deaths we have seen have been attributable to Covid. Suicide rates have not risen, and violence may have fallen. Pressure on the NHS is being increased by coronavirus, not lockdown, and would only grow if restrictions were lifted.

Claim: Danish study shows masks don’t stop the spread
Response: The study was only testing protection for the wearer, not others in the vicinity. Problems with its design were pointed out before it was conducted, and there is lots of evidence from around the world that mask-wearing is associated with a lower rate of increase in the spread of the virus.

The theory of the tradeoff between infectivity and lethality goes that a virus is programmed for survival. If it is too deadly, it will kill off its hosts. So if it starts to spread more, the lethality reduces, because if it didn’t, there would be nobody left to infect.

Sars-CoV-2 has a way around that conundrum. It infects people before they know they are ill. So anyone carrying the virus could be walking around feeling fine and spreading it. By the time someone has been admitted to hospital and is fighting for their life on a ventilator, transmission to other people has already happened.

“The fact the people die is almost like a side-effect,” said Prof Deenan Pillay, a virologist at University College London.

One possible reason is that the increased transmissibility that we have been seeing in the virus is a result of people having a higher viral load – more of the virus in their respiratory system.

“It would then follow if that is the mechanism, then, with more viral replication going on, you can imagine that could correlate with worse disease,” said Pillay.

Until now, that has not been documented, he says. Vallance said they did not think a higher viral load was responsible. He said it may be that the new variant binds more solidly to the receptor and gets into cells more easily or grows more readily in certain cell types.

There is clearly a lot more work to do before they get real answers and the data may not be sufficient yet for that. Pillay points out that the results come from people tested in the community. These are not people with severe illness in hospital so the sample size of those who die is smaller.

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Undoubtedly, this discovery is going to make other countries pull up the drawbridge on people wanting to visit from the UK. And that’s the right thing to happen, says Pillay. Border control has worked well in many places, such as Australia and New Zealand.

In fact, what this really tells us is just that we have got to use all the measures to control the virus that we know about already. There is no new way to deal with it. Increased lethality just means we have to try even harder not to catch it. Pillay points out that the first lockdown was more restrictive and better observed than the current one. There is more mobility, for one thing.

The news will strengthen hopes that we can be delivered from our sorry plight through mass vaccination, yet even that now looks less certain. There are suggestions that the variants originally found in South Africa and Brazil may be less susceptible to the vaccines we are now using.

The Mail reported remarks apparently made by the health secretary, Matt Hancock, at a webinar for travel agents. He said there was “evidence in the public domain” that the South African variant reduces vaccine efficacy by “about 50%”. Although he followed up by saying: “We are not sure of this data so I wouldn’t say this in public.”

The good news is that the vaccine manufacturers have consistently said they can tweak the vaccines to deal with variants – and there are indications that they are working out whether and how to do exactly that right now.