Mr Van-Tam warned those who have had the vaccine could still be “spreading the virus” and putting other vulnerable people at risk. It is not yet known whether the coronavirus vaccine prevents the transmission of Covid-19.
It takes two to three weeks after receiving a vaccine dose before it takes effect and people can still catch the virus during this time.
Writing in the Daily Telegraph Mr Van-Tam said: “Even after you have had both doses of the vaccine you may still give Covid to someone else and the chains of transmission will then continue.
“If you change your behaviour you could still be spreading the virus, keeping the number of cases high and putting others at risk who also need their vaccine but are further down the queue.
“No vaccine has ever been 100 percent effective so no-one will have 100 percent protection from the virus.
“Despite the speed of the rollout, these are people who will not have the vaccine for a while yet.
“Regardless of whether someone has had their vaccination or not, it is vital that everyone follows the national restrictions and public health advice, as protection takes up to 3 weeks to kick in and we don’t yet know the impact of vaccines on transmission.
“The way to reduce everyone’s risk is to break the chains of transmission and really push down the number of cases.”
Thus far the UK has vaccinated a higher proportion of its population than any other country except Israel, the United Arab Emirates and Qatar.
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On Saturday a record 478,248 people received the vaccine.
The Government has chosen to prioritise giving as many vulnerable people as possible their first coronavirus jab before they start distributing the second.
Mr Van-Tam defended this policy in his article writing: “Some people are questioning the UK policy of trying to give as many at-risk people as possible the first dose of vaccine in the shortest possible time, inevitably extending the interval before the second dose is given.
“But what none of these (who ask reasonable questions) will tell me is: who on the at-risk list should suffer slower access to their first dose so that someone else who’s already had one dose (and therefore most of the protection) can get a second?
“Everyone on the JCVI [Joint Committee on Vaccination and Immunisation] priority list is at risk from this nasty virus, and vaccines just can’t be produced at an unlimited rate.”
Thus far the UK has recorded over 97,329 coronavirus deaths, more than any other country in Europe.
Deaths are counted as coronavirus related if they take place within 28 days of a person testing positive for Covid-19.
Currently more than 37,000 people are in hospital in the UK suffering from coronavirus.
More than half of those aged over 80 in Northern Ireland have received their first dose of the vaccine.