by Silvia Turin
The fourth dose (or booster) strengthens the immune system. less effective at blocking infection but protects against illness or death and is important for the elderly and infirm. The important thing is to do it: the differences between the vaccines are minimal
Can Covid vaccine recalls prevent a surge in cases? Not quite, but they protect those at risk (and others too) from a serious illness and Long Covid.
The contagion
As all studies that have followed over time have confirmed, each new variant of the SARS-CoV-2 virus undermines the previous one, especially in terms of transmission capacity (contagion). This is called the Immune Evasion ability: Each time, the variants perform a little better, overcoming some barriers put up by vaccines and previous infections. Not quite, it is written: The spread is not blocked, but definitely limited by vaccination. And above all, serious risks are limited.
The new variants
As of this week, the BQ.1 subvariant (nicknamed Cerberus) and its subline BQ.1.1 have been responsible for 49.7% of Covid-19 cases in the United States. They mostly outperformed the BA.5 variant.
It is also found in Europe, where the BQ types are now widespread in France and the UK.
In Italy, the last flash poll on the variants, carried out by the Istituto Superiore di Sanit (ISS) on November 8th, still shows the dominance of BA.5 (equal to 91.5%), but the sequences BQ.1 and BQ.1.1 are increasing significantly with a prevalence of 30.7%.
As the New York Times writes, Dan Barouch, head of the Beth Israel Deaconess Center for Virology and Vaccine Research, found that the new variant BQ.1.1 is about seven times more resistant to immune defenses than BA.5 and 175 times more resistant than the original coronavirus (Wuhan).
Vaccine efficacy in Italy
For this reason, vaccine efficacy also decreases from updated vaccines (hence booster shots or booster shots). Contagion is possible, as is reinfection, but the vaccine barrier (or created by previous infections) still resists. The data on reinfections monitored in Italy in the last week is 7.2% (according to the extended ISS report of November 11). The vaccine continues to offer high protection in preventing hospitalizations and deaths: even small improvements in immunization response to booster vaccinations can have important positive public health implications.
During the Omicron prevalence period (from January 3, 2022), the vaccine’s efficacy in preventing major disease in Italy was 69% in those vaccinated with an incomplete or complete cycle and 82% in those vaccinated with an additional dose or booster dose.
In the most vulnerable groups (over 80 years old), the rate of ICU hospitalizations is currently 4 times higher for unvaccinated than for those who received a booster and 7 times higher than for those who received the fourth dose.
Any recall is good for defense
The vaccines are updated and the variants follow one another, it seems like a race against time, but not lost: each recall strengthens the defenses. For this reason, the Ministry of Health in Italy has not indicated one type of vaccine but another for the recall. Vaccines have been upgraded to Omicron variants and have become bivalent. Pfizer-BioNTech and Moderna reported that their boosters produced four to six times higher levels of antibodies than the original vaccine (to BA.4 and BA.5 and not to BQ.1 and BQ.1.1). However, a range of other (preliminary) research suggests that updated boosters are only marginally better than the original vaccines.
What to do? Elderly, immunocompromised individuals and pregnant women should have a booster dose as the effectiveness of the vaccine decreases 4-6 months after each last dose and this particularly affects frail individuals. In Italy, the fourth dose campaign did not have the desired effect, with 8.2% of the population taking part.
Long covid and epilepsy
The vaccine also protects against Long Covid: in addition to all the well-known unpleasant consequences (brain fog, fatigue, shortness of breath, among others), a little-known one is monitored, Covid patients are 55% more likely to develop epilepsy or seizures in the six months after infection, and this increased risk was more pronounced in children than in adults. That’s according to a study by the University of Oxford in the UK.
Meanwhile, Pfizer and BioNTech have announced the start of Phase 1 clinical trials of a new-generation mRna anti-Covid vaccine candidate that may be effective against multiple variants of the pandemic coronavirus. The wildcard product is called BNT162b4 and is designed to boost immune memory T cell response and extend the duration of protection against Covid-19.
November 18, 2022 (Change November 18, 2022 | 21:12)
© REPRODUCTION RESERVED