Complete vaccination against COVID-19 is highly effective at preventing hospitalisation, emergency department visit, and intensive care admission due to infection with the virus, according to a study involving data from nearly 200 hospitals around the US.
The real-world evidence, published in the New England Journal of Medicine on Thursday, was gathered from electronic health records (EHRs) which demonstrate that the vaccines provide high levels of protection for populations disproportionately affected by the virus.
The US Centers for Disease Control and Prevention (CDC) collaborated with six US healthcare systems plus the Regenstrief Institute, to create the VISION network to assess COVID-19 vaccine effectiveness.
All these institutes contributed hospitalisation and ICU data for patients older than 50 years of age from a total of 187 hospitals, in addition to data from emergency departments and urgent care clinics.
Data analysis showed two-dose mRNA vaccination — Moderna and Pfizer — was 89 per cent effective at preventing COVID-19 hospitalisations, and 91 per cent effective at preventing emergency department or urgent care visits.
The two-dose vaccination was 90 per cent effective at preventing COVID-19 intensive care unit admission, the researchers said.
The effectiveness was significantly lower in individuals who received only the first dose of the two shot-vaccination, they said.
”This study confirms that these vaccines are highly effective,” said study lead author Mark Thompson, a member of the CDC COVID-19 Response Team.
”They offer significant protections for people older than 85, people with chronic medical conditions, as well as Black and Hispanic adults. All are groups who have been hit particularly hard by this disease,” Thompson said.
The researchers said they hope this finding will convince more people to get vaccinated to protect not only themselves, but their community.
The study also looked at the effectiveness of the single-dose Johnson and Johnson vaccine.
It was found to be 73 per cent effective against emergency department and urgent care visits, and 68 per cent against hospitalisations.
However, the authors of the study noted that the smaller sample size may affect the precision of these estimates and state that more data is needed.
”This real-world evidence corroborates the results of clinical trials and provides even more confidence in the vaccines,” said research paper author Shaun Grannis, a professor at the Indiana University School of Medicine, US.