Paul Hunter

Will Covid turn into the common cold?

Will Covid turn into the common cold?
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Many experts and modellers thought that the 19 July reopening would be a disaster. So far, that has not been the case. Daily case numbers actually started falling within days after 19 July, although that was far too soon to have been caused by anything to do with ‘freedom day’. The question now is how the pandemic will play out for the rest of this year and the next? In trying to understand this, we need to understand some important things about the biology of coronaviruses and their interaction with their hosts: us.

Sars-CoV-2, the virus that causes Covid, is not going away. Like other coronaviruses, it will likely infect us all repeatedly throughout the rest of our lives, probably about once every five years. Vaccines will blunt its path, but will protect less against infection over time (while still protecting against hospitalisation and death). Herd immunity will never happen but we will get to a manageable balance between immunity and infections.

Covid will be a different disease. Within a few years, the vast majority of infections will be asymptomatic or mild nose and throat illnesses. In other words, like the other coronaviruses, it will simply become another cause of the common cold. Indeed, the Zoe Covid Symptom Study has shown that symptoms are already becoming more familiar: the Delta variant usually manifests as a sore throat and runny nose.

The other coronaviruses are seasonal and tend to peak in the winter. We can expect this virus to do the same. After this year, we will see winter surges for years and decades to come, but will see fewer and fewer deaths. Later this year, the third vaccines that will be offered to the vulnerable, along with flu jabs, will be essential to reducing illness and protecting the NHS. Recent suggestions that people who were given AstraZeneca in the spring should be given Pfizer or Moderna for their third shot are sensible, given the greater immune response triggered by the mRNA jabs.

What about the risk of new variants? Could they derail our return to normal? It was a variant that plunged us into a five-month lockdown just as the vaccines arrived last Christmas. New variants create problems because they are much more infectious or because they escape immunity. There are reasonable grounds, however, to believe that the Delta variant may be the virus's end point.

When any virus jumps host, it is rarely a good fit immediately. The virus is the key, and its host – us – is the lock. After a virus jumps, there is very rapid evolution until one variant becomes the best fit between key and lock. The best-fit variant soon becomes dominant and evolution slows dramatically. While we cannot be certain that Delta is indeed the best fit, it certainly seems close, and I doubt we will see a similar surge from another variant. As we can see with other coronaviruses, further mutations do arise that can make the virus less controlled by prior immunity, but each ‘escape’ mutation is not in itself enough to completely evade prior immunity or vaccines. Substantial protection will still remain.

The worst of the pandemic is behind us, at least in the UK. But it is essential that the booster shots rollout is successful. If that goes well, prolonged restrictions are unlikely to be needed again. We are in a fortunate place: many other countries would see quarrelling about ‘pingdemics’ as a luxury as their health services threaten to collapse. The UK has better days – and years – ahead.