Exactly a year ago, the World Health Organization received information about a new infectious disease, the causative agent of which was still unknown at that time. In one year, science gained an unprecedented amount of knowledge about the SARS-CoV-2 coronavirus and presented several vaccines against it. However, some questions are still not answered.
How strong is immunity against coronavirus
Individual experts and officials can make very bold predictions about the duration of vaccine action. However, it was simply not possible to find out how long the immune system protects against re-infection with coronavirus: it takes time.
Information about the persistence of immunity after vaccination, based on four months of observations after, is currently known only for the vaccine manufactured by Moderna. The study showed that the number of antibodies in the blood of people vaccinated with it exceeds that of those who have recovered from COVID-19. Scientists point out that this is incomplete information: monitoring of the level of immune cells (T and B lymphocytes) is still ongoing. For other vaccines, information is even more limited to date.
After suffering COVID-19, according to a recent study, protection lasts for at least eight months. Scientists have found in the blood of those who have recovered specific memory cells for the coronavirus, which are able to quickly trigger the production of antibodies. How long it can last remains to be seen.
Does vaccination stop disease transmission
The main question that coronavirus vaccine research is answering is how effective vaccines are in preventing the symptomatic form of COVID-19. What criticism is the design of these studies, you can learn from our material.
One unanswered question remains whether the vaccine only prevents symptomatic cases or completely suppresses transmission COVID-19-19. To do this, she must prevent asymptomatic infection, since carriers of the virus who do not have symptoms can also infect others.
Only the developers of the Oxford vaccine provided data on asymptomatic cases after vaccination. Of the 6,638 UK study participants who completed a PCR test, asymptomatic infection was found in 29 vaccinated and 40 unvaccinated.
Why some people suffer the disease more severely than others
One of the “mystical” questions of the pandemic is why some people get sick in a mild form, while others are severe. There are a number of assumptions why people from risk groups (with chronic diseases, the elderly, men) develop a serious illness more often. So far, however, they remain speculations.
The role of genetic and environmental factors remains a mystery. This is illustrated by a study of the course of COVID-19 in identical twins who lived together and worked in the same job. One of them had a mild illness, but the other developed severe complications. In this case, scientists have not found a single risk factor that could provoke such a different course of the disease.
How long is the “long covid”
It is known that after suffering COVID-19, some pathological symptoms can persist for months. They can occur not only in those who have had a severe or moderate illness. A recent study showed that even a third of people who were treated at home for a mild coronavirus infection have at least one post-coid symptom after 30-45 days. These symptoms include weakness, shortness of breath, and loss of smell and taste. Less often people are “haunted” by coughs, chest pain, headache.
What counts as “long covid”, how common the problem is, and how long the painful symptoms may persist remain to be determined.
What will happen to the virus when the pandemic ends
Experts believe that after the end of the pandemic, the SARS-CoV-2 coronavirus will remain with us for a long time: it may become one of the seasonal colds. The extent of the infection will depend on many factors (for example, how many people will be vaccinated against the coronavirus, how persistent the immune system will be).
COVID-19 can become a seasonal infection with annual outbreaks if immunity against it lasts about 40 weeks – as is the case with seasonal coronaviruses. If the immunity is more persistent, then epidemics will be more rare. Mass vaccinations have the potential to prevent them.