COVID Q&A Can common cold protect against Covid, and why no AZ booster?

Q Can catching a cold protect me against Covid infection?

A A study from University College London seemed to suggest that recovering from a common cold could protect you against Covid-19.

Scientists studied 58 hospital staff who treated Covid patients in the early stages of the pandemic, yet never got ill and repeatedly tested negative for the virus.

But it wasn’t that they avoided the virus – instead, their immune systems were better at destroying it before it had a chance to replicate inside the body.

All of the volunteers had higher levels of immune system cells called T-cells, which were capable of killing Covid. T-cells remember previous infections so they can prevent them happening again.

But why were these NHS workers’ immune systems so good at attacking Covid-19, a new virus?

The researchers’ theory is that their T-cells had been triggered by recent exposure to a much less destructive type of coronavirus – a distant cousin of Covid that causes the common cold.

The significance of the research is that scientists may be able to exploit it to develop vaccines that target the internal machinery shared by all types of coronavirus – including Covid.

This might potentially get round the problem of new strains being resistant to existing jabs, and prevent some colds in the process.

Q Why is the Oxford/ AstraZeneca vaccine not being given as a booster?

A Almost 11.5million people across the UK have so far received their third Covid jab. But only a fraction of those have been given the Oxford/AstraZeneca vaccine, even though it was widely used for first and second doses.

Instead the Government has sanctioned the use of the Pfizer and Moderna jabs, because there’s evidence that they trigger a stronger immune reaction.

Data published by Pfizer showed that it is roughly 96 per cent effective at protecting against infection when used as a booster.

Other studies have shown the benefit of mixing jabs, so patients may see greater protection if they had AZ for first and second doses, and Pfizer for a booster. Patients can receive an AZ booster if they previously suffered a reaction to Pfizer or Moderna jabs.