Covid booster shots are highly effective against hospitalization

The Omicron variant is spreading all over the world at an alarming rate, reaching even the world’s most remote islands – many of which managed to stay protected from the coronavirus for over two years before this highly contagious strain hit. 

However, the situation in several countries, including previous epicenters such as South Africa and the United Kingdom, suggests that the Omicron waves are much shorter and less damaging than the Delta ones, with case numbers rising rapidly to unprecedented highs and afterwards steeply declining, and hospitalizations and deaths remaining relatively low. Currently, the United States also appears to have reached its Omicron peak, and is now embarking on its downward slope. 

Sadly, hospitalization and death rates in the U.S. remain disproportionately high, compared to those in more vaccinated countries such as the UK, Spain, or Portugal. Three new studies led by the Center for Disease Control and Prevention (CDC) and published on Friday, January 22, 2022 have highlighted the importance of mRNA (Pfizer BioNtech and Moderna) booster shots for preventing severe Omicron illness. These are the most comprehensive and reliable assessments to date of the role boosters played in United States’ Omicron wave.

In one study, scientists investigated hospitalizations and emergency room visits from August 26, 2021 to January 5, 2022, and found that vaccine effectiveness against hospitalization with Omicron fell to 57 percent for people with two doses of mRNA vaccines, but that a third shot restored the protection to 90 percent. 

A second study analyzed nearly ten million Covid cases and over 117,000 associated deaths and found that booster shots reduced significantly the number of both symptomatic infections and deaths caused by Covid-19, particularly among people aged 50 and older.

Finally, a third study published in the journal JAMA has compared the effectiveness of booster shots against symptomatic infection with Delta, respectively Omicron, in over 70,000 people. While boosters are indeed less protective against symptomatic infection with Omicron than with Delta, they are still providing a much higher level of protection than vaccination with only two doses.

“The data here show the protection provided by vaccines and the importance of being up to date on your Covid-19 vaccination, which for tens of millions of Americans means getting a booster dose,” said CDC Director Rochelle Walensky. 

“A booster is essential for preventing severe disease, hospitalization, and deaths,” added Eric Topol, a professor of Molecular Medicine at Scripps Research. According to him, public health officials need to communicate clearly that, although the vaccines and booster shots are “not holding up against Omicron infections, they are holding up the wall against severe disease … and that’s phenomenal.”

Further research is needed to assess the usefulness of boosters in younger and healthier individuals. In the meanwhile, the need to initiate the vaccination scheme for a very large number of people in the United States and abroad remains crucial for avoiding future Covid-19 waves and the emergence of new – and possibly more deadly – coronavirus variants.   

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By Andrei Ionescu, Earth.com Staff Writer