UK Edition
Why is Boris Johnson having to self-isolate given he has already had Covid?
Boris Johnson says he is 'bursting with antibodies' after being told to self isolate, several months after recovering from Covid-19
The Prime Minister said he was as “fit as a butcher’s dog” and “bursting with antibodies” in a video message announcing the news that he has to self isolate.
“The good news is that NHS Test and Trace is working ever more efficiently,” Boris Johnson said in a video posted to Twitter on Monday. “The bad news is they pinged me and I’ve got to self isolate because somebody I was in contact with a few days ago has developed Covid”.
Mr Johnson met Ashfield MP Lee Anderson at Downing Street on Thursday – the following day Mr Anderson lost his sense of taste and later tested positive for Covid-19.
The incident raises questions about whether Downing Street is a “Covid-secure workplace” and why visitors are not tested ahead of time.
But why is the Prime Minister having to self-isolate given he has already had Covid and should, as he suggests, have some level of immunity to the disease? The answer is partly medical but mostly to do with public health messaging – and setting the right example.
NHS Test and Trace does not discriminate between those who have and have not had Covid when contacting people about the need to self isolate. It can't because it does not hold data on those who have previously tested positive and – even if it did – it is not yet clear how much protection an earlier infection confers.
There have been just 25 cases of reinfection documented world wide, with the majority of the reinfections being either mild or asymptomatic.
However, several cases have been more serious, with the first reinfection death reported last month. The case involved an 89-year-old woman in the Netherlands who had a rare type of non-Hodgkin lymphoma which compromised her immune system.
The jury is still out on whether coronavirus reinfection is likely to be a big problem. Dr Simon Clarke, associate professor in cellular microbiology at the University of Reading, said: “It remains to be seen whether this is going to be a very rare occurrence or whether the [repeat] cases we have seen are the first in a bigger wave.”
Mr Johnson’s characteristically upbeat claim to be “bursting with antibodies” was also questionable, said Dr Clarke.
Firstly, antibodies quite rapidly fade with time, so Mr Johnson would have had to have undergone a recent antibody test to know he still had them - more than six months after first contracting coronavirus. A study conducted by Imperial College last month that involved 365,000 people showed that antibodies in the population fell by more than a quarter in three months.
But secondly, having antibodies does not necessarily guarantee immunity. Even the latest vaccines which cause your body to create antibodies are only 90-95 per cent effective – leaving five to 10 per cent still vulnerable.
“No one really knows what the correlates of protection are. That is, what the facets of your immune system are that make you immune. You might get a really stonking antibody response but you might not get enough of the antibodies that are important. So a strong antibody response does not of itself prove that you’re going to be protected,” said Dr Clarke.
Most experts think a recent infection will be protective for the great majority so to some extent the medical argument can be cast as a dancing on the head of a pin. More important, perhaps, is the public health message the Prime Minister would send if he failed to follow the rules.
A substantial portion of the UK population suspect they may have had Covid mildly in the first wave but have no way of knowing for certain.
Dr Clarke said: “If people think they’ve had it when in fact they haven’t that potentially poses all sorts of problems if they’re exposed to someone who has the disease and they go round spreading it.”
It is inconvenient to say the least that the Prime Minister is once again locked away in his Downing Street flat as this crucial moment in the nation’s history. In Britain’s plans for the next pandemic expect a lengthy and detailed chapter entitled: protecting the country’s leadership – better measures for keeping the country moving.
It will almost certainly involve moving the prime minister and others outside of the airless warren that is 10 Downing Street and a proper screening of visitors.
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