Revealed: How common cold can protect you from the virus

A COMMON cold could help to protect people from getting Covid-19, a study suggests.

Evidence showed some of those who did not catch the virus may have immunity likely to have come from previous colds.

A study of 52 people in the UK who were recruited rapidly after someone they lived with caught Covid found that half had avoided infection.

Blood tests showed around a quarter of that figure had white blood cells called memory T-cells – which can kill off the virus. In contrast, none of the 26 people who caught the virus had the same T-cell protection.

Scientists say the cells emerged in people whose immune system previously fought off common colds caused by similar viruses to the one which causes Covid.

The findings may explain why some people avoid getting ill after coming into contact with the virus while others become sick.

Researchers suggested children often do not catch Covid because of immune protection after being exposed to lots of colds at school, while those who are older are more susceptible because they mix with fewer people.

However, not all common colds are caused by viruses similar to Covid, and not everyone would gain protection from those that are. Experts also said they remain sceptical about the level of protection provided by colds.

Professor Ajit Lalvani, senior author of the study at Imperial College London, said: ‘This finding is considered something of a holy grail for understanding why some people resist infection despite being exposed to Covid.

‘We now know having had a common cold can protect people because the immune system is clever and can use the past exposure to a distant cousin of the current coronavirus.’

Researchers believe the study could pave the way for a new generation of ‘variant-proof’ jabs.

Current vaccines are less effective when the ‘spike’ the virus uses to get into cells mutates – as it did with Omicron. But a vaccine focused on proteins deeper within the virus, which T-cells target, could work well no matter how the virus changes in the future.

Professor Lalvani said the new vaccines could last for a few years rather than their protection waning after several months.

The research, published in the journal Nature Communications, follows a similar study from University College London in November which looked at 752 healthcare workers in London, among whom 58 were exposed to the virus but not infected. Uninfected hospital staff had similar T-cells likely to have come from colds.

However, Dr Simon Clarke, associate professor in cellular microbiology at the University of Reading, said the study should not be ‘overinterpreted’.

He added: ‘It seems unlikely that everyone who has died or had a more serious infection has never had a cold caused by a coronavirus. It could be a grave mistake to think that anyone who has recently had a cold is protected against Covid-19.

‘Similarly, there is no measurement of how much protection the reported effect gives people.’

‘Immune system uses past exposure’