The real invincible star? Research reveals that 3 doses of vaccine + natural infection with O virus have nearly 80% protection
Is mixed immunity better than natural infection? Study reveals differences in effectiveness
The Omicron virus is constantly mutating. Will vaccination plus natural infection be the “invincible star” against the virus? The latest study, published in the New England Journal of Medicine on June 15, compared vaccine protection, “natural immunity” from infection with variant strains, and “hybrid immunity” from infection with the virus plus vaccine. It was found that the protective power of BA.2 for those who had been infected with the virus was only 46.1%, while the protection for those who had been infected and confirmed plus 3 doses of vaccine reached 77.3%.
This study mainly analyzes the “natural immunity” protection and vaccination protection of people who have had symptomatic infection, and the difference between the two against Omicron virus subtypes BA.1 and BA.2. Research shows that the protection against BA.2 is 46.1% for symptomatic infection, 52.2% for three doses of RNA vaccine and no infection; 55.1% protection for those who have been diagnosed plus 2 doses of RNA vaccine; 55.1% for those who have been infected and received 3 doses The vaccine has the best effect, with a protective power of 77.3%.
3 doses of vaccine plus virus protection multiplied by 80%
In addition, regardless of whether they have been diagnosed without vaccination, only received RNA vaccine, or mixed immunity with infection and vaccination, the protection against moderate and severe cases reaches 70%. The research team claimed that there was no significant difference in protection against BA.1 and BA.2 symptomatic infections, regardless of past diagnosis, vaccination, or mixed immunity. Judging from the data, mixed immunity indeed provides the strongest protective effect.
Studies have pointed out that the confirmed natural immunity effect can reduce the risk of infection by about 50%, while the protection of the third booster dose of vaccination is about 60%, and it is estimated that the additive effect of the two types of protection should be 80% (1- (1-0.5)×(1- 0.6)=0.8), and research data shows that the protective power of this group is 77.3%, which is quite close to the predicted value. At the same time, the effectiveness of vaccination in preventing infection by mutant strains was once again confirmed.
Virus spike protein highly mutated hybrid immunity maintains longer
So far, the main consensus among scientists is that mixed immunity provides better protection against mutant strains of the new coronavirus than vaccination alone or previous infection. One study pointed out that those who received 1 dose of vaccine and were diagnosed had a 58% lower risk of reinfection; those who received 2 doses of vaccine and were diagnosed with “mixed immunity” could reduce the risk of infection by 66%.
However, most of these studies were conducted before the Omicron pandemic, and the spike protein of Omicron and its subtypes has been highly mutated compared with the original virus strain. Whether it affects the protective power of mixed immunity is not yet known.
According to public information from the World Health Organization, vaccination combined with immune stimulation from 2-3 natural infections will form “mixed immunity” and increase the chance of preventing Omicron infection. Victoria Hall, an epidemiologist at the British Health and Safety Authority in London, also pointed out that whether vaccinated alone or diagnosed, the protective effect will decrease over time, but groups with “mixed immunity” can maintain longer-term protection.
Neutralizing antibodies increased 100-fold? RNA vaccines better stimulate T cells
Some studies have also found that neutralizing antibodies after infection and then vaccination are 100 times higher than natural immunity from infection alone, and 25 times higher than vaccination alone. The increase in the strength of the antibody response is thought to be related to memory B cells.
In addition to producing antibodies against the virus when reinfected, B cells also encode a reservoir of antibodies, which can be said to be a “preemptive” preparation for the immune system to fight against viruses it has not been exposed to. The production of B cells requires the driving of T cells. Among various vaccines, RNA vaccines seem to have a greater stimulatory response to T cells in people who have been diagnosed.
Another preprint paper pointed out that no matter which vaccine is vaccinated, the new crown vaccine will increase the memory bank of T cells, which can reduce the risk of severe illness regardless of whether it has been diagnosed before, and the booster dose can provide more than the original setting of the vaccine. protection, triggering greater antibody recognition and reducing hospitalizations. Major countries such as the United Kingdom have also begun planning to administer the fourth and fifth doses of the vaccine to immunocompromised groups.
source:
COVID vaccine plus infection can lead to months of immunity
Effects of Previous Infection and Vaccination on Symptomatic Omicron Infections
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