Initial findings on the Delta variant of SARS-COV-2 indicate that the people vaccinated against COVID-19 may transmit the highly contagious strain as easily as the unvaccinated, Public Health England (PHE) said.
The findings come after the US Centers for Disease Control and Prevention (CDC) raised concerns that vaccinated people infected with Delta could, unlike with other variants, readily transmit it.
The highly infectious Delta variant, first detected in India, has become the dominant coronavirus type globally, sustaining a pandemic that has already killed more than 4.4 million people.
Vaccines have been shown to provide good protection against severe disease and death from Delta, especially with two doses, but there is less data on whether vaccinated people can still transmit it to others.
“Some initial findings, indicate that levels of virus in those who become infected with Delta having already been vaccinated may be similar to levels found in unvaccinated people. This may have implications for people’s infectiousness, whether they have been vaccinated or not. However, this is an early exploratory analysis and further targeted studies are needed to confirm whether this is the case,” PHE said in a statement.
According to the report, the Delta variant now accounts for more than 99 percent of COVID-19 cases across the UK. Out of 1,467 patients hospitalized with confirmed cases of Delta variant, 55.1 percent were unvaccinated while 34.9 percent had received both doses of the vaccine.
Nearly 75 percent of the British population has had two vaccine doses, and PHE said that “as more of the population gets vaccinated, we will see a higher relative percentage of vaccinated people in the hospital.”
Separately, PHE said another variant, known as B.1.621, first detected in Colombia, had shown signs of evading the immune response triggered by either COVID-19 vaccines or previous infection. PHE has labeled the variant “under investigation” but has not declared it as a “variant of concern”, a designation that can trigger strong policy responses.
“There is preliminary laboratory evidence to suggest that vaccination and previous infection may be less effective at preventing infection with (B.1.621). However, this data is very limited and more research is required. There is no evidence to suggest that (it) is more transmissible than the dominant Delta variant,” it said.