You might have noticed that some people who have been vaccinated assume now they’ve had their jab, they can do away with masks altogether. The logic? Surely they can’t get Covid, or pass it on, if they’ve had the vaccine? Wrong. 

Paul Hunter, a Professor in Medicine at the University of East Anglia, explains: “The vaccine does not prevent all infections and you can still be infectious even after vaccination with any of the current vaccines. Also, you can still get sick.”

He and other scientists are urging people to keep wearing face masks after being vaccinated with the first and second doses of the Covid-19 vaccine.  

So why is it important to keep wearing masks? Well, we still don’t know how much vaccination stops infection and subsequent virus transmission. Studies have shown some reduced transmission after vaccination, but it’s not enough to suggest it stops you passing on the virus if you have it. After having the jab, there’s still a possibility you could catch the virus, not develop symptoms, but pass it on to someone who isn’t vaccinated – who could become very sick.

Face masks are a major factor in preventing infected individuals from spreading the virus, says Lawrence Young, Professor of Molecular Oncology at Warwick Medical School. “Wearing a face mask after you’ve been vaccinated is still important,” he says. “Face masks can stop you getting infected – they can act as a barrier against airborne droplets and also keep your nose warm and moist which also inhibits infection.”

It’s also important to remember it takes time for vaccines to protect you – another reason why mask-wearing is crucial. Dr Peter English, a retired consultant in Communicable Disease Control and past chair of the BMA Public Health Medicine Committee, explains: “The level of protection builds for at least four or five weeks after the first dose, and for at least another week after the boost. So, until then, you are not as well protected as you will eventually be.”

Currently, 32m have received the first dose of the Covid-19 vaccine in the UK, while just over 7.5m have received their second dose and are therefore deemed fully vaccinated. But there’s still some way to go before all adults are vaccinated – the government has set itself a deadline of the end of July to have offered everyone over the age of 18 their first dose. 

Even then, children will remain susceptible to the virus – unless a vaccine is approved for them soon – as will those who choose not to have the jab. People who are pregnant are also unable to have the vaccine unless they’re deemed high risk, while some who are immunosuppressed have been able to have the vaccine, but their bodies haven’t necessarily generated a strong response.

On top of this, there’s also the concern of mutating Covid variants, which some vaccines might not work as well against. There’s been a surge in cases of the South Africa variant in south London, which Dr Julian Tang, clinical virologist at the University of Leicester, says reinforces the need to wear masks. 

“One of the ideas behind maintaining social distancing, masking, etc. is to protect us from exposure to vaccine escape variants like the South African B.1.351 variant, whilst more of the population is being vaccinated,” he says.

The good news is that if people maintain social distancing and masking until all – or most – of the adult population are vaccinated, the overall viral replication rate across the population will be suppressed enough to reduce the probability that new vaccine escape variants will arise, he explains. It would also reduce the circulation of variants like the South Africa and Brazil that are already here.

“Ongoing social distancing and masking will protect those who have not responded to or have refused the vaccine,” he says, “whilst awaiting the larger scale population vaccine suppressive effect on viral replication overall.”

In the US, people who are fully vaccinated (with two doses) can mix, even indoors and without masks, as long as they’re well and don’t have symptoms. Dr English says it may be that, when a greater proportion of the UK population has been fully vaccinated, similar rules might be introduced here too.

But until then, wear your mask.