More than 75% of Spaniards have already received the complete vaccination guidelines against SARS-CoV-2. The benefit of vaccines in Spain has been spectacular, as a recent study with data from the Ministry of Health has shown.
The impact has been more important in the most vulnerable population, that is, the one with a higher risk of hospitalization and death. In fact, the mass vaccination of those over 60 prevented a fourth wave of covid-19 income and deaths from occurring last April, after Easter. However, there was then a high number of new diagnoses, confirming that vaccines do not prevent transmission but severe pneumonia.
During the summer we have had one last wave of covid-19, produced by the delta variant of the coronavirus, which is much more transmissible. The cases have occurred mainly in young people and in the unvaccinated. We have just released the autumn and the pandemic crisis seems to be under control in Spain. So do we rule out a new wave?
Covid-19 in Israel
The protection provided by vaccines appears to last no more than 6 months, as the latest data from Israel shows. That country was the one that vaccinated more quickly a greater proportion of its adult population. However, since July there has been a large wave of new cases of SARS-CoV-2 infection in Israel. Of course, the proportion of serious forms has been low. More importantly, hospitalizations for COVID-19 have been 20 times less frequent in those who had received a third dose of the vaccine.
It has been argued that perhaps the vaccines administered so far could be less effective against the new delta variant, which is much more transmissible and which has spread around the world from India. However, this does not appear to be the case and the efficacy is largely maintained, at least after two doses have been received.
So why the recent resurgence of new cases of SARS-CoV-2 infection in Israel? It seems that there are several reasons:
- the irruption of the highly transmissible delta variant;
- the return to school of the children, the only group that had not been vaccinated;
- family gatherings on the occasion of Jewish religious holidays;
- the massive and repeated practice of diagnostic tests in the country, which has revealed many asymptomatic or mild cases;
- and the main reason, which seems to be the progressive loss of efficacy of the vaccines administered during the first quarter of the year.
An experience similar to that of covid-19 in Israel has been lived in Iceland, a country of just 350,000 inhabitants in the Arctic Circle. Almost all of their adults had been vaccinated before the summer. Despite this, new cases were on the rise in August after the delta variant burst. However, there were hardly any serious cases and only one patient has died.
Covid-19 in the United States
In contrast, the pandemic is still very active in some southern states of the United States, where the vaccination rate is low, less than 50%, and the delta variant is transmitted very quickly. During 2020, more than half a million Americans died from covid-19. Compared to previous years, mortality in 2020 experienced an increase of 18%. SARS-CoV-2 infection was the third leading cause of death in the United States, behind only cardiovascular disease and cancer.
A few days ago, the United States government approved the administration of the third dose of the Pfizer vaccine for three population groups: the elderly, the immunosuppressed, and personnel at risk of high exposure to the coronavirus (health workers, educators, public services, etc.). Additional doses for Moderna and Janssen vaccines are also expected to be approved soon. The justification for a third dose in the elderly and immunosuppressed is clear: in them the immune response to the vaccine is lower or disappears more quickly.
More debatable is the administration of a third dose in personnel with high risk of exposure, such as health workers and educators. In either case, booster doses provide additional protection. And while they may be unnecessary for some, they will be more protective for most, especially as time goes on.
Vicente Soriano, Faculty of Health Sciences & Medical Center, UNIR – International University of La Rioja
This article is republished from The Conversation under a Creative Commons license. Read the original article.
