How to give the third dose of vaccine? Is Moderna really better than BNT? Dr. Huang Gaobin explains the truth about Omicron
People are rushing to get the third dose of Moderna vaccine. Are they afraid of “immune paralysis” if they take too many doses?
Omicron’s high contagiousness has caused a sudden increase in the number of local cases since January, and the command center called on those who are eligible to receive the third dose of the vaccine as soon as possible. Recent studies have found that neutralizing antibodies rise the most after the third dose of the Moderna vaccine, causing people to rush to get the Moderna vaccine and “it’s hard to get one dose.”
Dr. Huang Gaobin, deputy dean of infection control at China Medical University, pointed out that from a research perspective, the booster dose of Moderna is indeed more effective, but the booster dose of Moderna in Taiwan is 50 micrograms (half a dose). If you cannot make an appointment with Moderna, you can also choose the BNT vaccine. However, it is not recommended that those who received BNT in the first two doses should also receive BNT in the third dose. Judging from the three doses of BNT administered in Israel, the protective effect is obviously worse.
“It will be better to use mRNA for booster doses of vaccine. In principle, we should try to use a “mixed dose” instead of a single vaccine!” Dr. Huang Gaobin pointed out that it is recommended to give a mixed dose for the booster dose of the vaccine. The only way to get the same vaccine continuously and the protection is still within acceptable range is to take 3 doses of Moderna vaccine.
In the face of the continuous discovery of new mutant strains of Covid-19, will the future move towards regular annual vaccination, or will a fourth dose of vaccine be required? Dr. Huang Gaobin believes that it is not certain whether to take the COVID-19 vaccine once a year, but it is currently not recommended to take a fourth dose of the vaccine to avoid immune paralysis in the body. This year, next-generation vaccines from Moderna, AZ, and BNT are coming out one after another, and they may be the main weapons against various mutant strains in the future.
Neutralizing antibody concentration cannot sustain T cell immune responses for a long time and is also important
“The effect of the vaccine is not only based on neutralizing antibodies, but also the immune response of T cells!” Dr. Huang Gaobin pointed out that the protective effect of the vaccine mainly lies in neutralizing antibodies and T cells. Neutralizing antibodies can directly neutralize the virus entering the body in the acute phase and are the first line of defense against the virus. However, it is impossible for the human body to maintain a high concentration of neutralizing antibodies, which will inevitably decrease over time. At this time, T cells must be relied on to fight the virus.
Dr. Huang Gaobin explained that there are two types of T cell protection. One is to store antibodies in T cells. The next time you are infected, the T cell memory will be awakened and the corresponding antibodies will be produced. Second, T cells produce proteins to eliminate cells that have been infected by the virus, so they are also called “killer cells.” Therefore, the protective power of the vaccine cannot only depend on the titer of neutralizing antibodies.
Omicron has high risk of reinfection and breakthrough infection, no need to panic
Omicron’s high contagiousness has caused a significant increase in “breakthrough infection” cases, and vaccination may not be effective? Dr. Huang Gaobin explained that as long as there is a vaccine, “breakthrough infections” will occur. No vaccine can achieve 100% protection. Breakthrough infections are medically normal, so there is no need to panic.
“Omicron is not only highly contagious, but also has a high chance of reinfection. You may still get it after being infected with other mutant strains!” Dr. Huang Gaobin said that the types of vaccines currently used in Taiwan seem to have acceptable protection against Omicron, but The effect will not be obvious until the third dose. We call on the public to get vaccinated as soon as possible to protect themselves and their relatives and friends around them.
In addition, some studies have claimed that “monoclonal antibodies” are less effective against Omicro. Dr. Huang Gaobin pointed out that the monoclonal antibody therapeutic drugs currently used in Taiwan (Casirivimab + imdevimab and Bamlanivimab + etesevimab) can still achieve therapeutic effects on Omicro. He appealed to the public not to worry too much, to maintain epidemic prevention vigilance at all times, wash hands frequently, and wear masks to reduce the risk of infection. Risk of infection.
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