Vaccines against covid-19 offer greater protection than immunity resulting from a previous infection, according to a study released by the U.S. Centers for Disease Control and Prevention.

According to this study, unvaccinated people who were infected months earlier are five times more likely to get covid-19 than those who had complete vaccination and no previous infection.

The study emphasizes that "vaccines confer increased protection against symptomatic forms of Covid-19″.

The study was done in nearly 1900 hospitals in nine states, and researchers analyzed about 7,000 adult patients who were hospitalized this year with respiratory illnesses or Covid-19-like symptoms.

About 6,000 of these patients were fully vaccinated with Moderna or Pfizer injections between three and six months before hospitalization, while another 1,000 were not vaccinated but had been infected with covid-19 in the same time period.

About 5% of the vaccinated patients tested positive for SARS-CoV-2, compared to about 9% of the patients in the unvaccinated group.

The researchers also considered other data, such as age and the intensity of virus circulation in different areas to conclude that the unvaccinated group was at a higher risk of contracting the disease.

The study supports some previous research, including research that found higher levels of antibodies in vaccinated patients than in others who had contracted the disease.

Still according to the researchers, not enough data has been collected to draw any kind of conclusion about Johnson & Johnson's vaccines.