New COVID19 vaccines from Pfizer and Moderna seem to be effective in preventing COVID19 infection. However, it is uncertain how well these vaccines can contain the spread of the virus. Both companies have analyzed the number of people, who have been infected with the virus after being vaccinated. It is possible that vaccinated people catch the infection without having any symptoms and then continue to spread the virus if they come in close contact with other people or do not wear masks. Health experts have said that if vaccinated people become a silent spreader of the virus, they will continue to infect others and will put the unvaccinated population at risk. An immunologist from Stanford University, Michal Tal has said that many people think that once they are vaccinated they do not need to wear face masks. He has said that it important for people to wear masks even if they are vaccinated as they still can spread the virus.
Experts have said that in most respiratory diseases, including coronavirus, the nose is the main affected area, which provides the virus an entry into the human body. The virus rapidly replicates there. It jolts the immune system to produce antibodies, which are specific to the mucosa, it is a moist tissue lining in the nose, lungs, mouth, and stomach. For the same person who is infected for the second time, the immune cells, which are familiar with the virus, shut it down there in the nose before it infects other parts of the body. COVID19 vaccine is injected into the muscles, which quickly get absorbed in the bloodstream. It stimulates the immune system to generate antibodies, which provides enough immunity to the vaccinated person from getting ill again. Some of these antibodies float around the nasal mucosa to evade the virus right then and there. However, it is uncertain how much of the antibody pool can be activated and how soon it can be mobilized. If it is not mobilized soon, the virus can thrive in the nose and can be transmitted while sneezing, breathing, and interacting with others.
Another immunologist from the University of Washington Marion Pepper has said that it depends whether the virus can multiply faster or the immune system can prevent it faster. He has said that it is the reason mucosal vaccines or nasal sprays such as FluMist or oral polio vaccine are better at preventing the infection as compared to intramuscular shots. Experts hope that the next generation coronavirus vaccines might be able to protect the nose area and the rest of the respiratory tract. In the future, people might be able to get intramuscular shots followed by a mucosal boost, which might be able to trigger protective antibodies in the nose and throat. As per the experts, the lungs, the site of severe symptoms of the illness are more accessible to antibodies as compared to the nose, or throat. The New COVID19 vaccine has been proved to be 95 percent effective in preventing symptomatic illnesses; however, it might not be that effective in preventing all kinds of diseases. Experts have said that preventing severe types of diseases is easy but preventing mild diseases might be hard for the new vaccines. The vaccine trials have not made data public on how many people have been diagnosed with a second infection after being vaccinated. Pfizer is planning to test a subset of participants from its trial for antibodies against a viral protein known as N. As per the experts, N antibodies might be able to reveal whether the participants of the trial have been infected with the virus after being vaccinated. Moderna is also going to follow the suite and test its volunteers for N antibodies.