Cases of contagion and serious illness drop "substantially" with the third Pfizer dose.
This is underlined by a study published in the "New England Journal of Medicine", based on data from the Tel Aviv Ministry of Health.
The infection rate, he notes, at least 12 days after the booster, is "11.3 times" lower than the two doses, while "the serious disease rate is 19.5 times lower".
The research was conducted from July 30 to August 31 on 1.13 million people aged 60 and over who had completed immunization five months earlier, divided into two groups: those given the third dose and those who have received two.
Compared to the Delta variant, the study reads, the third Pfizer dose "would bring the efficacy of the vaccine among those who received the booster to about 95%, a value similar to the efficacy of the original vaccine reported against the Alpha variant" .
Specifically, 12 days after the booster dose, the confirmed infection rate was lower in the booster group than in the no booster group by a factor of 11.3; the severe disease rate was lower by a factor of 19.5.
In the primary analysis, the confirmed Covid-19 rate and the severe disease rate were compared between those who had received a booster injection at least 12 days earlier (booster group) and those who had not received a booster injection. (non-recall group).
In the secondary analysis, on the other hand, the infection rate four to six days after the booster dose was evaluated versus the rate at least 12 days after the booster.
The researchers concluded that rates of confirmed coronavirus and serious illness were "substantially lower" among those who had received a booster (third) dose of the Pfizer vaccine.
Severe illness "was defined as a resting respiratory rate greater than 30 breaths per minute, less than 94% oxygen saturation when breathing ambient air, or a ratio of arterial partial pressure to lower inspired oxygen fraction to 300 ".
(Unioneonline / F)