Seven months after vaccination, there is no reduction in the efficacy of mRna vaccines in the general population, while there is a slight decrease in protection from symptomatic or asymptomatic infection in some specific groups.
This is what emerges from the fourth report, by the working group of the Istituto Superiore di Sanità and the Ministry of Health ‘covid-19 vaccine surveillance’ on the joint analysis of data from the integrated covid-19 surveillance and the national vaccine register. Thus in a press release the ISS.
Long Covid less likely if you get infected after the vaccine
by Daniele Banfi
We reviewed data from more than 29 million people who received at least one dose of the mRna vaccine, followed up until August 29, 2021. Efficacy was assessed by comparing the incidence of symptomatic and asymptomatic infections, hospitalizations and deaths. at different time intervals after the second dose with that observed in the 14 days after the first dose, considered as the ‘control period’.
The report, in particular, highlighted that in the general population seven months after the second dose there is no significant reduction in efficacy in terms of protection from infection (symptomatic or asymptomatic), which remains at 89%. Even against hospitalization and death, protection remains high (96% and 99%) six months after the second dose.
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The study then highlighted that in immunocompromised people there is a reduction in the protective effect against infection starting from 28 days after the second dose. The estimate, in this case, presents a high variability due in part to the small number of subjects included in this group but also connected to the diversity of the pathologies present in this category.
The note edited by the ISS also states that in people with comorbidities there is a reduction in protection from infection, from a 75% risk reduction after 28 days from the second dose to 52% after about seven months.
One of the conclusions of the document focuses on the slight decrease, while remaining above 80%, of the efficacy against infection in people over 80 and in residents of the RSA.
It’s not all. Comparing the data between January and June 2021, the period in which the alpha variant predominated, with those between July and August, with a delta prevalence, the report shows a reduction in efficacy against infection from 84.8% to 67.1 %.
Third dose, because some have doubts and prefer to wait
by Giuseppe del Bello
However, the effectiveness against hospitalizations remains high (91.7% against 88.7%), while the apparent reduction in the effectiveness of vaccines in preventing infection could be due to the time elapsed after vaccination and / or to a decreased effectiveness. against the delta variant. Behavioral changes as a result of relaxation of other preventative measures, such as wearing masks and physical distancing, may also have contributed.
Finally, the text underlines how the data are consistent with those obtained from the comparison with the unvaccinated, published weekly in the extended report of the ISS and how it is essential to continue this type of updates and monitoring in future months.
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