RESEARCH/covid-19: One dose of vaccine reduces the risk of transmission in the home by almost half

A dose of vaccine against Covid-19 could halve the risk of a person being vaccinated transmitting the coronavirus to other unvaccinated members of the same household, according to a new British study, the most comprehensive to date on how vaccine immunity affects the virus.

The discovery that people who develop the infection Covid-19 after vaccination they are much less likely to infect others, raising hopes that the spread of the disease could be significantly slowed down, even among young people who have not yet been vaccinated.

The study, based on data from the Public Health England (PHE), according to the Financial Times and the Guardian, included more than 57.000 close contacts with around 24.000 households where at least one person had vaccinated, compared to almost one million non-vaccinated contacts.

The statistical analysis compared the probability of transmitting the coronavirus from one vaccinated person to others, compared to an unvaccinated person. Those who became infected three weeks after the first BioNTech / Pfizer or Oxford / AstraZeneca vaccine were given were 38% to 49% less likely to transmit the coronavirus to other unvaccinated people in the same household.

Protection was observed from about the 14th day after the first dose, regardless of the age of the vaccinated. Experts are examining whether the two doses of vaccines can further reduce the risk of transmission from vaccinated to unvaccinated.

British Health Secretary Matt Hancock said the findings were "fantastic news" and showed that "vaccines are the best way out of a pandemic, as they protect you but can also prevent you from unknowingly infecting someone in your home". .

Although the study is "very encouraging," according to PHE's Dr. Mary Ramsey, even vaccinated people should continue to behave as if they had the virus, taking precautions such as good hand washing and keeping a distance from others. .

A few days ago, another British study was conducted by the University of Oxford and the National Statistics Office, which also concluded that vaccines not only protect the person being vaccinated, but also reduce the risk of transmitting the coronavirus to others. According to that analysis, a single dose of BioNTech / Pfizer or Oxford / AstraZeneca reduces the risk of transmission by almost 66% and in particular by 74% the risk of infection Covid-19 with symptoms. After two doses of Pfizer / BioNTech, the reduction in transmission increases to 70% and the symptomatic infection to 90% (for the Oxford / AstraZeneca vaccine, the two doses are longer, there is not yet enough data to draw safe conclusions). ).

Source: RES-EIA