The opinion of drug agencies around the world after the summit and the caution of EU health ministers. In Israel, the fourth doses do not stop the infections. The choice to strengthen the campaign for the third dose and help the frail
Looking at the data on the impact of Omicron it is becoming increasingly clear that a booster dose is needed to extend vaccine protection, but administration of multiple booster doses at short intervals of time is not a sustainable approach In the long term, this was highlighted by a report on anti-Covid vaccines signed by drug agencies around the world after the world summit held under the aegis ofInternational Coalition of Medicines Regulatory Authorities (Icmra) on January 12.
Not recommended by the authorities
Today the health ministers of the member states, together with the EU Commissioner for health, Stella Kyriakides, met by videoconference to talk about this issue also on the basis of the report provided by the regulatory agencies. Clear science on the next steps for citizens to take – said the Commissioner -: increase the spread of vaccination and provide an additional booster, especially for the most vulnerable. If we see conclusive data on the need a fourth dose, we’ll have to be ready to act, he concluded.
Today, talking about the fourth dose for everyone is extremely premature and misleading, does nothing but lead to misunderstandings, echoed Pierpaolo Sileri, Undersecretary of Health, who spoke to the microphones of Radio Cusano Campus. An experimental project was made where it was seen that it could be useful for certain subjects, he specified: If you ask me today if we will have to do another dose of vaccine in October, I answer that it is conceivable, perhaps only some categories will have to do it. Perhaps a recall will be needed if this virus continues to circulate.
Not scheduled in Italy
In Italy for now there is no talk of the fourth dose: the campaign for the booster, the third dose, is underway, which has reached 49% of the eligible population and which protects very well from Omicron (especially against unfavorable outcomes).
What does science say about the doses after the second? First, we must consider that it is normal to do the third dosesindeed, they are the true completion of the vaccination cycle. Normally they are done 6-12 months after the second doses, but in this phase they have been anticipated for the arrival of the fourth wave. With three doses the vaccination cycle is truly complete: all the vaccines used (except those based on live attenuated viruses which require a single dose) are based on three doses. That said, the fourth dose would make sense in two cases from an immunological point of view – al Courier service Sergio Abrignani, immunologist at the State University of Milan – (we talked about it WHO
): due to a decline in immunological memory or because the variant that circulates largely escapes the “old” vaccine and therefore the fourth dose should be based on the Spike of the new variant. The hypothesis of the fourth dose, as pointed out by the regulatory authorities, must be carefully examined: Based on what we know, if you vaccinate every two to three months to continuously stimulate a strong immune response (which we call “effector”) and which works well in the short term, after a while the opposite effect could be achieved. The immune system could “anergise” (anergy the inability of an organism to react to infections or to contact with an inoculated substance with antigenic power, ed.). There is a risk of the paradoxical effect of “paralyzing” the immune response, says Abrignani.
The fourth dose does not stop the infections
It is more plausible to think of recalls for fragile people, waiting for more data. Meanwhile, the first results arrive from Israel (we have written about it WHO) who began administering the fourth dose of the Covid vaccine to healthcare workers, over 60s and frail patients. The second booster doesn’t seem to provide much protection
against contagion from Omicron variant. Although it did increase up to five times the level of neutralizing antibodies, the result not sufficient to counter Omicron infection. We have seen many people infected with Omicron after the fourth dose. A little less than in the control group, but still a lot, said Gili Regev-Yochay, director of the Infectious Diseases Unit of the Sheba Medical Center of Tel Aviv. The research was conducted on 150 people who received a fourth dose of Pfizer 2 weeks ago and 120 others, who had done three Pfizer doses, received a fourth dose with Moderna (all healthcare professionals) a week ago.
Strengthen the third doses
The aforementioned report from regulatory agencies also highlighted that current vaccines offer one less protection against infections and mild illnesses caused by the Omicron variant. However, they continue to offer significant protection from hospitalization and severe Covid-19, especially after a booster dose.
For now the choice is to face the Omicron wave by enhancing the third doses, which serve not to clog hospitals. Later, after the peak and the months after the third recall, it will be possible to evaluate what to do based on the epidemic situation in progress and which variants will be present.
January 21, 2022 (change January 21, 2022 | 18:04)
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