Recently, I have been discussing the flu vaccine and COVID-19 infections. First, I debunked anti-vaccine myths. Second, I explained that the seasonal flu vaccine might be helpful in improving outcomes for patients who contract the coronavirus.
However, at that time, I wanted to make it clear that:
Once again, I am not making any claim that the seasonal flu vaccine will prevent a coronavirus infection. It’s just about comorbidities, that is, other health conditions that increase one’s risk for dangerous outcomes from the disease.
Because COVID-19 is a respiratory disease, anything that weakens the respiratory system could (and again, we don’t have solid information on the pathophysiology and comorbidities for the disease) lead to a worse course for the disease. And that would include a higher risk of mortality.
The flu vaccine can reduce the risk of one coronavirus comorbidity since the flu is a respiratory disease. So, the flu vaccine isn’t going to help reduce your risk of coronavirus infection, but it will reduce your risk of complications, including death, from COVID-19.
In addition, preventing the flu may help to reduce hospitalizations and ICU admissions, allowing for more capacity for patients who have contracted COVID-19.
But again, I assumed that the flu vaccine would have little effectiveness against SARS-CoV-2, the virus that causes COVID-19. This seemed biologically plausible because, as opposed to what Donald Trump claims, the flu virus and coronavirus are vastly different organisms. The two viruses are actually in two different phyla, meaning that the influenza virus and coronavirus are as closely related as a human is to a lobster.
There appeared to be no scientifically supported reason to believe that the flu vaccine actually prevents COVID-19. However, there seems to be some intriguing, preliminary, and potentially convincing evidence that the flu vaccine may have some effect on the risk of COVID-19. Continue reading “Flu vaccine and COVID-19 infections – some evidence it might lower risk”