17/08/2021
Why are vaccinated people still testing positive for Covid but not getting as sick?
Itโs All about the type of immunoglobulins produced from vaccination. For those of you who are hardcore scientists, ignore this post- itโs geared toward lay people and meant to be easy to understand. Iโm going to do an epic under-simplification of a very complicated subject. Look away!
IgG is a type of immunoglobulin (antibody) that is plentiful in our blood serum. These are the immune proteins that our Covid vaccine is really good at producing.
IgA is a type of immunoglobulin that is plentiful in our mucous membranes, like the respiratory tract (nose and throat). Unfortunately, our injected vaccines are NOT very good at creating a lasting army of this type of antibody.
SARS-Cov-2 (virus) that causes the disease Covid-19 is a respiratory virus- meaning, that it enters the body through the respiratory mucosa. It sets up shop in the area of the back of the throat where the nasal passage meets, called the nasopharynx. While itโs there, it enters those cells and reproduces. Once it reproduces in high enough numbers, it moves itโs way down the respiratory tract and attacks lung cells. From there, it enters the whole body and attacks almost every organ system.
When you are vaccinated, your mucous membranes in the back of your throat are still relatively unprotected, because they lack the IgA antibody response at the mucous membrane level. This is why a vaccinated person is still showing high viral loads in their nasopharynx area when swabbed. However, once the virus tries to move down into the lungs, the very good vaccine induced IgGs that are circulating in a vaccinated personโs blood serum, quickly identify the virus and begin destroying it. The body then says, hold onโฆwhereโd these guys come from? The antibodies see the open door at the nasopharynx and then move the troops to destroy. This is the reason that vaccinated people are not getting as sick, even though they are getting technically infected and why vaccinated people are contagious for less time than unvaccinated people are. Our defense is delayed, at the upper respiratory tract, but we eventually have a neutralizing response.
This is why it became important for even vaccinated people to begin wearing masks. We still have several days of the virus successfully replicating in the backs of our throats, which means that when we cough, sing, laugh, talk loudlyโฆ.we can pass those viruses to other people. This is new with the delta variant because it is better at unlocking those respiratory cells than other variants were. This is what changed. The previous variants were not as good, and it took them longer to unlock cells and replicate so our vaccine induced serum antibodies used to have more time to recognize and respond than they do now.
So what youโre seeing with vaccinated infected people is: sudden onset sore throat, dry cough from nasopharynx irritation, eventually a fever as the virus tries to make it down the respiratory pathway and your immune system activates, but then a marked reduction in symptoms that suggest that the virus has been unsuccessful at invading any other organ systems. This is your reduction in hospitalizations and deaths. The lungs never get so sick that the person requires oxygen. Vaccine IgGs are very effective at staving off a massive infection, but not great at stopping the virus from initially replicating in the throat.
This might suggest that we should focus efforts/funding into more research and development for nasal spray type vaccines (several are in trials) that produce better IgA response for virus neutralization at the mucous membranes which would be better at halting transmissions of the virus between people.
https://stm.sciencemag.org/content/13/577/eabd2223
https://pubmed.ncbi.nlm.nih.gov/34133415/
