Remember the polio vaccine that was administered on a sugar cube? As it turns out, that vaccine may prevent against infection with SARS-CoV-2. The vaccine in question is the oral polio vaccine (OPV), a live-attenuated virus vaccine. A thread. (1/n)
microbe.tv/twiv/twiv-604/
microbe.tv/twiv/twiv-604/
It is a known fact that there are viruses that are persistently present in the population and that you can always isolate such viruses from healthy children. These viruses replicate “under the radar” and don’t cause disease. (2/n)
A couple of examples include several adenoviruses, rhinoviruses, etc. Back in the polio days when they were conducting clinical trials for OPV, they found that these other viruses were completely wiped out in children who had received OPV. (3/n)
In fact, initial administration of OPV reduced mortality caused by other pathogens by 30%. Each successive booster increased this favorable effect even further. This was observed in several parts of the world because it stopped outbreaks caused by completely unrelated viruses. (4
This effect is also observed after vaccination with other live-attenuated vaccines like the measles vaccine, smallpox vaccine, and bacterial vaccines like BCG and others. To the extent that we know, there are no antibodies for polio that cross-react with these other viruses. (5/n
So what is the mechanism for protection against these other viruses? The effect would most definitely have to be non-specific, which implicates the innate immune response. This is the immune response that reacts first, whenever your body encounters a new pathogen. (6/n)
Some speculate that interferon plays a role because it makes cells more resistant to other viruses. But it may just be possible that recent vaccination simply engages the innate immune response and keeps it “on guard”. (7/n)
This is one of the hypotheses for why kids are not as affected by SARS-CoV-2. Clinical trials are planned to analyze the efficacy of OPV in protecting against SARS-CoV-2 infection. (end)
