Double vaccinated people can still spread Covid amongst their households, latest research shows.
People with both jabs can be just as infectious as the unvaccinated warn experts studying UK household cases.
Even if housemates have no or few symptoms, the chance of them transmitting the virus to other unvaccinated housemates is 38 per cent.
This drops to 25 per cent if housemates are also fully vaccinated.
The Lancet Infectious Diseases work shows the benefits of people being fully vaccinated scientists behind it say.
Prof Ajit Lalvani, of Imperial College London, UK, who co-led the study, said: “The ongoing transmission we are seeing between vaccinated people makes it essential for unvaccinated people to get vaccinated to protect themselves from acquiring infection and severe Covid-19, especially as more people will be spending time inside in close proximity during the winter months.
“We found that susceptibility to infection increased already within a few months after the second vaccine dose - so those eligible for booster shots should get them promptly.”
According to the study, which ran from September 2020 to September 2021 people who are double jabbed have a lower, but still appreciable, risk of becoming infected with the Delta variant.
It also found vaccinated people clear the infection quicker than the unvaccinated but their peak viral load (when people are most infectious) is similar.
The research comes as all remaining countries on England’s red list for international travel will be removed by Transport Secretary Grant Shapps.
The Cabinet minister announced that the Latin American countries of Colombia, Dominican Republic, Ecuador, Haiti, Panama, Peru and Venezuela will be taken off the list at 4am on November 1.
This means arrivals will no longer need to spend 11 nights in a quarantine hotel at a cost of £2,285.
Mr Shapps wrote on Twitter: “We will keep the red list category in place as a precautionary measure to protect public health and are prepared to add countries and territories back if needed, as the UK’s first line of defence.”
He added that from Monday, the Government will recognise coronavirus vaccines for arrivals from more than 30 new countries and territories including Peru and Uganda.