A new large-scale study says that people, who are vaccinated against influenza, may be partially protected against many severe effects of COVID-19 and are less likely to be hospitalised.
The research, done on nearly 75,000 COVID patients from around the world, showed that people who got the annual shots of influenza had reduced risks of stroke, sepsis, deep vein thrombosis (DVT) from COVID-19 and they were also less likely to visit the emergency care or get admitted to ICUs, the scientists said.
"This finding is particularly significant because the pandemic is straining resources in many parts of the world," said Devinder Singh, a professor at the University of Miami Miller School of Medicine in the US.
He said that the research has "the potential to reduce the worldwide burden of COVID disease."
The researchers screened de-identified electronic health records held on the TriNetX research database of over 70 million patients to identify two groups of 37,377 patients.
While the members of the first group had got the flu vaccine between two weeks and six months before getting COVID-19, the members of the second group got the infection but were not vaccinated against the flu.
The study, present online at the European Congress of Clinical Microbiology & Infectious Diseases (ECCMID), showed that people who did not receive the flu jab were up to 20% more likely to get hospitalised.
The study, conducted on people from countries including the US, UK, Germany, Italy, Israel and Singapore, also said that people without flu shots were 58% more likely to visit the emergency department. They were also up to 45% more likely to develop sepsis, up to 58% more likely to have a stroke, and up to 40% more likely to have DVT.
However, having the flu shot did not reduce the risk of death, the researchers said, and added that it is not known how exactly the influenza jab gives protection against COVID-19.