The goal of the supplemental booster is to strengthen the immune response conferred by the two-dose vaccination course, based on data showing a decline in protection over the long term in older individuals and vulnerable people.
The third dose of the Covid vaccine, which in Italy will initially be intended for immunocompromised people, will also be administered in the United Kingdom, where it will be offered to all over 50s and the frail from next week. The goal is to strengthen the immune response conferred by the two-dose vaccination course, based on the data available so far and which show a decline in protection in the long term.
Green light UK at the third dose
In the case of the United Kingdom, the data published on Tuesday by Public Health England, which highlighted the decrease in the effectiveness of vaccines over time, in terms of protection from symptomatic infection and from the risk of hospitalization and death, are decisive. The reduction, the data for age groups and categories of people show, was faster in the elderly and people with pre-existing health conditions.
Efficacy over time of Covid vaccines against symptomatic infection, hospitalization and hospitalization / PHE
The administration of the third dose “will ensure that the protection provided by vaccines will be maintained in the winter months in those who are most at risk of developing severe forms of Covid-19”Pointed out the PHE, with the aim of avoiding further pressure in hospitals during the winter. Experts from the British Department of Health have in fact predicted a resumption of influenza and other respiratory infections, beyond the winter wave of coronavirus, as a result of the complete removal of the restrictions decreed by the Johnson government last July.
The third dose of Covid vaccine works: in Israel the risk of infection has been reduced by 10 times
As in the countries that have decided to administer doses booster, the UK campaign will primarily rely on Pfizer’s vaccine, although some people will be offered it a half dose of Moderna “following scientific evidence showing that both vaccines provide a strong booster response“. The administration, adds the British Department of Health, will be independent of the vaccine used for the first vaccination cycle, but if neither of these two vaccines can be used, for example because there is an allergy to the components of one of the two vaccines, the Advisory Committee British (JCVI) recommended to use the Astrazeneca vaccine for those who received this serum for the first and second dose.
Professor Saul Faust of the University of Southampton, lead investigator of the clinical trial that underpins the data used by the UK Government Advisory Committee, said the booster doses have increased “of several times”Antibodies and cellular immunity against the Sars-Cov-2 virus. The doses used are the standard ones, i.e. those already used for the first vaccination cycle, although some companies are working on updating the formulations so that they can deal with new variants. However, scientists believe this “upgrade” will not be necessary. “The original versions developed for the Wuhan strain still offer excellent protection – said Professor Faust -. I suspect we won’t have to change the vaccines for Delta”.