How long is the protection of the booster dose against the Omicron variant?

The booster dose of the COVID-19 vaccine loses its effectiveness in protecting against the omicron variant from ten weeks after its application, according to a study on the risks of the strain prepared by the United Kingdom Health Security Agency (UKSHA).

The Agency, which publishes a report every week with the main data on the evolution of the variant, has warned that those related to the effectiveness of the vaccine against the symptomatic disease and the rate of reinfection confirm “Substantial immune-evading properties.”

Although he has indicated that there is no data “enough“To make an assessment of the efficacy in severe disease for omicron compared to the delta variant, the UKSHA has pointed out that preliminary evidence shows that the” decrease in the efficacy of the vaccine against symptomatic infection occurs more quickly ” with the new variant.

“This is visible, as expected, after the time after the second dose, and it can also be the case after the booster dose after ten weeks”, the agency has asserted.

Specifically, it has estimated between 15 and 25 percent the reduction in protection after that the tenth week since the administration of the booster vaccine. However, it has affected that the efficacy of the vaccine against severe disease is maintained, especially after that dose.

On the other hand, the UKSHA has determined that in cases of omicron variant infection the relative risk of hospitalization decreases, compared to delta, according to three analyzes carried out in United Kingdom and whose results coincide with data from South Africa.

The agency has specified, however, that these analyzes are preliminary because the number of infected with omicron currently hospitalized is “scarce“And the spread of the variant in older age groups is”limited”.

“There is not enough data on the severity of the disease once in the hospital or mortality. The available data suggest that the risk reduction observed in United Kingdom it is probably partly a reduction in the intrinsic severity of the virus and partly due to the protection provided by previous infection ”, has stated the UKSHA, adding that it is not possible to“ quantify with certainty ”the relative contributions of these two factors in the present.

Thus, it has warned that despite the “lower” risk of hospitalization observed, the rapid growth of cases – it has a higher risk of transmission than delta – and the immune-evading properties of omicron “may give rise to a number of very high hospital admissions ”.

The risk of hospitalization, ‘encouraging’

The Health Minister, Sajid Javid, has described the report’s data on a reduced risk of hospitalization as “encouraging”, but has pointed out that the British Government’s concern continues to be the impact of the spread “Extremely fast”.

“Since we have been learning about this variant, our strategy has been to buy time, time to evaluate and to prepare our measurements. There is still a lot of concern, but we are learning more about it ”, has added in a video broadcast on his Twitter profile.

In this way, he has stressed that the “best” form of protection against the pandemic and the omicron variant continues to be vaccination. “Although two doses of the vaccine are not enough, we know that boosters offer significant protection against the variant and preliminary evidence suggests that this strain may be less severe than delta,” he said.