We had already announced that twelve months after being fully vaccinated, a third booster dose of the Pfizer COVID-19 vaccine would likely be necessary. Today it is confirmed that it will be like this, specifically at nine months, or at the latest at twelve.
In addition, as also confirmed by the co-founder of the German pharmaceutical company that makes Pfizer, Ugur Sahin, every year or eighteen months another dose will be needed.
Periodic booster doses
The data provided by the pharmacist itself establish that the efficacy of the Pfizer vaccine is progressively decreasing over time, and can go from 95% to 91% in just six months.
People should also be vaccinated against the coronavirus annually, as for seasonal flu, because there are also indications that the immune response induced against SARS-COV-2, as well as natural, is gradually reduced.
We know that our immunity to different coronaviruses decreases over time, as with the four common cold coronavirusesTherefore, there is always a sufficient number of people who have lost their immunity to allow viruses to continue to circulate and cause respiratory diseases. This seems to be the same scenario for SARS-COV-2, so we will have to vaccinate, at least for now, just as we do to combat other coronaviruses.
The vaccine will also need to be adjusted to cover new coronavirus variants as they emerge, such as the one that has recently appeared in India.
The advantage of mRNA vaccines like Pfizer’s is that they are much easier to update than ‘viral vector’ vaccines like AstraZeneca’s. Furthermore, with vaccines using AstraZeneca technology a patient cannot be repeatedly immunized because they are likely to develop immunity to the adenovirus vector (the delivery vehicle) itself.
Moderna (another mRNA vaccine) CEO Stephane Bancel has told CNBC that the company is also working to make booster doses available in the fall. The third dose would be prepared to provide the patient with greater immunity against the new strains and, especially, against B.1.351, better known as the South African variant.