Those fully vaccinated have some 50% protection against Delta

Researchers at Imperial College London found that people with a vaccine were half as likely to test positive for COVID-19 - including asymptomatic infections.

Considering those who had a symptomatic infection, they were at least 59% less likely to contract the illness when double vaccinated, Business Insider reported.

These estimations are lower than previous data presented by Public Health Data, which shows two doses of Pfizer's shot was 88% effective at preventing the symptomatic disease from the Delta variant, compared to 93.7% against the Alpha variant.

However, this study did not separate for the effectiveness of different vaccines, and the researchers said this was no reason for shock or concern, considering that PHE estimates were based on those who have symptoms and get tested, while the Imperial study was on a random sample of the population, designed to pick up more people.

"We're looking at effectiveness against infection amongst a random sample of the general population, which includes asymptomatic individuals," said Imperial epidemiologist Paul Elliot, according to Reuters, noting that the study tested people without symptoms, who may not have otherwise got a test: "So again, it's a different bunch of people."

The study also re-established a link between COVID-19 infections and hospitalizations, which began to wain, but now the Delta variant is causing to rise again.

MAH/PR