According to foreign media BGR reports, although the United Kingdom and the United States are carrying out the new crown vaccine, but researchers and health experts still can not say how long covid-19 immunity can last. In a recent interview, moncef slaoui, head of operation warp speed in the United States, shared encouraging news about the vaccine's immunity to the new coronavirus.The health expert said the vaccine may prevent infection for a limited period of time, but he expects the drugs to prevent severe covid-19 symptoms for three years after immunization.
Vaccination of Pfizer / biontech has begun in the UK and the US and will be followed up in Europe by the end of December. Phase 3 data showed that the drug was 95% effective and safe to block covid-19. The vaccine for Moderna will be reviewed on Thursday local time, and the FDA may approve the vaccine on the recommendation of an independent panel of research data. Moderna is also safe to use, with an effective rate of 94%. In all volunteers infected with the virus after vaccination, Moderna vaccine blocked severe covid-19.
The United States hopes to vaccinate about 20 million people with either vaccine in December. Regardless of the drug chosen, people who choose to use the vaccine so early need two doses to get the best protection, but the second dose needs to be reinjected after a few weeks interval. Researchers still can't say how long vaccine induced immunity will last, but the chief medical adviser to operation curvature has the best estimate yet.
Slaoui talked to Andrea Mitchell of MSNBC earlier this week about the new crown vaccine. He said the vaccine may not provide good protection against infection, but protection against severe covid-19 may last for quite a long time. "Prevention of infection... May last a short time, maybe three, four, six months," said slaoui. "In my humble opinion as an expert, disease prevention may last for a year, two years or three years."
A recent study showed that people who survived in early 2020 showed a strong immune response after about eight months. They still have neutralizing antibodies. But more importantly, they have new coronavirus specific B and t white blood cells that can recognize the virus and start the response immediately upon reinfection. These cells can raise a new generation of antibodies and kill newly infected cells.
Vaccine manufacturers have begun to study the B-cell and T-cell responses in volunteers receiving the drug during clinical trials. Pfizer / biontech vaccine can train the immune system to produce two types of T cells, help immune response in actual infection and selectively kill infected cells.
We already know that people may be infected with covid-19 more than once. It is reasonable to expect that some vaccinated people will be infected. But if slaoui's estimate is accurate, people may end up with more durable protection against infection than originally expected. In the past few months, health experts said they expected the vaccine to provide immunity ranging from six months to a year, similar to infection with one of the other four known human coronaviruses.