Scientists at the United Kingdom’s health regulator Public Health England on Friday flagged early signs that vaccination against Covid-19 may not prevent transmission of the Delta variant of the infection, Reuters reported.
The observation means that those who have been vaccinated against Covid-19 may be able to transmit the Delta variant as easily as those who have not been inoculated.
The highly transmissible Delta variant, which was first detected in India, has now been reported in 135 countries. It has become the dominant strain of the infection and triggered renewed restrictions in several countries, including the United States and China.
“This may have implications for people’s infectiousness, whether they have been vaccinated or not,” the Public Health England said about its findings on transmission of Delta variant. The health body, however, added that further targeted studies were needed to confirm the findings.
The observations, meanwhile, are similar to the findings of the United States’ Centers for Disease Control and Prevention. The CDC had in July described coronavirus as being “as transmissible as chickenpox” and warned that in some cases it could evade protection provided by the vaccines, reported Reuters.
The CDC report reiterated, however, that vaccines are highly effective in preventing serious illness, hospitalisation and death. In India, too, data on adverse events following immunisation showed that only 180 of the six crore people who received the vaccine died after taking the vaccine.
On the CDC report, All India Institute of Medical Sciences chief Randeep Guleria said that the American health body had compared transmission of the Delta variant to chickenpox as the disease has an R (reproduction) value of eight or more.
“That suggests that coronavirus is highly infectious,” Guleria said. “We saw that during the second wave in India, because entire families were getting infected.”
The R value measures how many people are being infected by one Covid-positive person on an average. For instance, a value between 0.7 and 0.9 means that every 10 Covid-positive people will pass on the infection to seven to nine others.
The number of infections keeps rising if the R value is more than 1. If the value declines, the infection will eventually stop spreading because there will not be enough new cases for the outbreak to continue.