Lockdown and social distancing could make our immune system weaker, says scientist

Prolonged periods of lockdown cocooning the public from germs could leave people dangerously vulnerable to new viruses, a leading epidemiologist has warned.

Sunetra Gupta, professor of theoretical epidemiology at the University of Oxford, fears intense social distancing could actually weaken immune systems because people are not exposed to germs and so do not develop defences that could protect them against future pandemics.

The scientist rose to prominence in March after her team’s modelling created a best case scenario where coronavirus arrived in the UK in December and spread quickly through the population creating “herd immunity”, already partly acquired through exposure to different strains of the virus.

Her research rivalled that of Professor Neil Ferguson, the Imperial College London professor whose worst case scenario of 500,000 UK deaths encouraged the Government into lockdown.

Prof Gupta told The Telegraph that while it was “unlikely” the three months of lockdown had compromised our immune system, there remained a possibility it had had an impact.

“This is a warning to not assume that the situation where we don’t suffer regular assaults by pathogens puts us in a better position,” she said.

“If we return to the point where we have no exposure, where we keep everything out and return to a state of existing as relatively isolated communities, we are like clumps of trees waiting to be set ablaze.

“That’s how things were in the age of pandemics.” She said the 1918 ‘Spanish flu’ pandemic which led to at least 50 million deaths was “such a shocker” because so many of those who perished were fit and healthy people under 40.

“That was because in 1918 there had been no flu at all around in Europe for 30 years,” she said.

“We weren’t globally connected then as we are now. Effectively we used to live in a state largely similar to lockdown 100 years ago, which created the conditions for the Spanish flu to come and kill 50 million people.”

She explained how “the fate” of any virus and our reaction to it depends on previous exposure to other strains of that pathogen. 

She claimed lessons can be learned also from European New World explorers who triggered a “virgin soil epidemic” when they landed among people who had had no previous contact with viruses both common and relatively harmless in the West.

“The kind of immunity that protects you against very severe symptoms and death can be acquired by exposure to related pathogens rather than the virus itself,” she said, explaining how there have been numerous strains of coronavirus.

“We do know populations were decimated in the New World with the introduction of pathogens. It can lead to very severe consequences at a population level having very little immunity from a lack of exposure.”

Prof Gupta is convinced international travel helps build up defences against emerging viruses, so the positives of easing restrictions outweigh the negatives. Britons have been on the move again recently, as the graphic below shows: 

She said: “The conditions for the spread of a virus have been enhanced by current practices of global mixing with worldwide travel. But, what also has been strengthened is the level of cross-protection we gain from exposure to different bugs.

“Overall, we are in a better place with all this international travel. So, the conditions where a pathogen might kill a lot of people has been reduced.” She said she expects a resurgence of Covid-19 in the winter months, but eventually the virus will end up like flu, a pathogen the public learns to live with and which claims a number of lives of vulnerable people each year.