What should people do if they have symptoms?
While there is no legal requirement to self-isolate, health experts such as the Covid Zoe study and the NHS recommend staying at home.
The Zoe team write: “If you’ve been vaccinated and start sneezing a lot without an explanation, you should stay home and get a Covid test, especially if you’re living or working around people who are at greater risk from the disease.
“Sneezing is a key way that viruses spread. Try to cover all coughs and sneezes with tissue or the inside of your elbow to minimise the spread of droplets. Avoid touching your eyes, nose and mouth until you wash your hands.
“Sneezing a lot could be a potential sign that someone vaccinated has COVID-19 and, however mild, should take a test and self-isolate to protect their friends, family and colleagues.
“Whether you’ve had your Covid jabs or not, we all still need to be careful to protect your own health as well as those around you in your family, workplace and community.”