In the New England Journal of Medicine a study, with residents of 280 nursing homes in the United States, has been published. A total of 18,242 residents were included, of whom 14,469 (80.4%) received the RNA vaccine from Pfizer and the other 3,573 (19.6%) from Moderna. Of all these vaccinated residents, 13,048 of them received the two doses of vaccine. Coronavirus infection was only detected in 1.4% of people who had received a single dose, decreasing the percentage of infection to 0.3% among those who had received both.
Protection with full doses
In another similar study carried out in Texas, 23,234 University employees divided into three groups were studied: unvaccinated (8,969 employees), people who had received only the first dose of the Pfizer vaccine (6,144 cases) and those who had received the complete vaccination regimen (8,121 people). It was observed that 234 employees (2.61%) of the unvaccinated group became infected by coronavirus and this only occurred in 112 (1.82%) of the people who had received a dose of vaccine and in 4 cases (0.05%) of the fully vaccinated group.
Therefore, from these studies it can be concluded that the efficacy of vaccination against COVID-19 is very high, even after receiving the first dose.