The study found that the incidence of COVID-19 was lower among those who received the flu vaccine.

Researchers from the Radbaud University Medical Center, along with colleagues from other universities and research centers in the Netherlands and Germany, found that those who received the flu vaccine were 47 percent less likely to contract the coronavirus during the first wave of COVID-19 and 50 percent less often during the second.

This was the largest study of its kind, analyzing de-identified patient records from across the globe and concluding that the annual flu shot significantly reduced the risk of stroke, sepsis, and DVT in patients with COVID-19.

Additionally, patients with COVID-19 who had received the flu vaccine were considerably less likely to meet the emergency department or be hospitalized in the ICU.

The study assessed patient records from several nations, including the United States, the United Kingdom, Germany, Italy, Israel, and Singapore. The team reviewed de-identified electronic health records from the TriNetX research database to identify two groups of 37,377 patients.

The two patient groups were then matched for risk factors associated with severe COVID-19 susceptibility, including but not limited to age, gender, ethnic origin, smoking, and chronic health conditions such as diabetes, obesity, and chronic obstructive pulmonary disease.

In the first trial group, people were vaccinated two weeks to six months before being diagnosed with COVID 19. The second group had COVID-19 but had not been immunised against the flu. The incidence of 15 adverse outcomes (sepsis, strokes, DVT, PE, arthralgia, joint pain, renal failure, anorexia, heart attack, pneumonia, ER visits, hospitalisation, ICU admission, and death) within 30, 60, 90, and 120 days of testing positive for COVID-19 were then compared.

The study indicated that people who had not received the flu shot were substantially more likely to be admitted to the intensive care unit (ICU) (up to 20 percent). Additionally, they were much more likely to attend the emergency room (up to 58 percent), acquire sepsis (up to 45 percent), suffer a stroke (up to 58 percent), and develop a DVT (up to 58 percent) (up to 40 percent). There was no reduction in the risk of death.

Although the mechanism by which the flu vaccine protects against COVID-19 is unknown, most ideas predict that the flu shot may increase the innate immune system — the basic defences we are born with that are not unique to any one illness.

According to the study’s authors, the findings strongly imply that the flu vaccine may protect against some serious COVID-19 effects. They also, however, strongly urge that individuals take COVID-19 vaccines in addition to their annual influenza vaccination.

They add that additional research, in the form of prospective randomized clinical trials, is needed to establish and better understand the possible link, but in the future, the flu shot could be used to augment protection in countries where the COVID-19 vaccine is in short supply or even to aid in the ongoing battle against COVID-19 breakthrough cases in those already vaccinated against the virus.

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