Third dose of the vaccine in Italy, the need to be pragmatic | by Giovanni Rezza

The
vaccination campaign in our country is proceeding at a brisk pace, and about 74 million doses of the vaccine have now been administered. Almost 35 million Italians, that is over 57% of the population
, have completed the vaccination cycle. We are therefore essentially in line with the other major European countries.

Vaccines have shown excellent real-world efficacy in controlling severe disease, reducing the risk of hospitalization and deaths, thus respecting the more than comforting data derived from experimental studies. While the mass vaccination campaign is being completed, one wonders about the next steps and, in particular, on the need to administer a third booster dose to all or part of the population.

The three questions

To solve this problem, it is now essential to answer some scientific questions:
1) how long the immunity conferred by vaccines lasts;

2) what role do the variants play in reducing the effectiveness and duration of protection;
3) if it will be possible to reach the so-called herd or community immunity.

How long is the protection given by the vaccine?

To the first question

we still don’t know how to fully answer, given that the follow-up of vaccinated people is still too short. It seems that, even if the neutralizing antibodies tend to decrease over time, the cellular responses and the memory of the encounter with the viral antigen persist. longer than previously thought. Of course, there is individual variability and, above all, Immunosuppressed people may find themselves in trouble first facing a viral attack.

Do variants make us more vulnerable?

The question relating to

variants even more complex. The beta variant (South African) appears to be the most resistant to vaccines, but fortunately its circulation is extremely limited in our country. As regards the delta (Indian) variant, vaccines remain highly effective in protecting us from severe forms of disease, but they are not always able to avoid infection. This means that, in a number of cases, the virus can continue to circulate among vaccinated people, while not causing the serious damage it had accustomed us to previously. Naturally, what has been said in relation to the first two questions has repercussions on the third.

Need a third dose?

Whereas

the virus is likely to continue circulating, we have to vaccinate as much as possible without thinking about achieving an ambitious goal like that of herd immunity, but rather to encourage a return to normalcy, protecting the population from the worst consequences of the disease and avoiding congestion in health facilities. Then when we have vaccinated a large part of the population, continuing for a while to maintain prudent behavior, we should also see effects on the reduction of the circulation of the virus. On the third dose, for now, it is better to refrain from the usual debate between pros and cons, starting to plan any recalls, to be carried out gradually, on the basis of needs and scientific evidence.