Header Ads Widget

Ticker

6/recent/ticker-posts

Will the second dose be given later than recommended, reducing vaccine effectiveness?

The interval between two doses of Covid-19 vaccine should follow the manufacturer's recommendations, if the second dose is slower than recommended, it will not reduce the effectiveness of the vaccine.

Specifically, the interval between two doses of AstraZeneca vaccine is at least 4 weeks, preferably 8-12 weeks. Two doses of Moderna vaccine are given at least 4 weeks apart. The Pfizer vaccine is given as two shots at least 3 weeks apart. Two doses of Sinopharm vaccine 3-4 weeks apart.

According to the current guidelines of the Ministry of Health, people who have received a single dose of a vaccine are best given the second dose with the same type of vaccine. People who have been vaccinated with Sinopharm, Pfizer, and Moderna vaccines are prescribed two injections of the same type. In case of limited vaccine resources, if the first dose is AstraZeneca vaccine, the second dose of Pfizer vaccine can be mixed. The interval between two injections is 8-12 weeks.

Many people are worried that they will have to start over again because of the time limit for the second dose of the vaccine. The doctor said: "So far, there is no recommendation to start the vaccine again and late injection does not reduce the effectiveness of the vaccine."

The doctor explained, an intensive study conducted in the UK on the gap between the two doses of the Pfizer vaccine produced an antibody-producing immune response and a T-lymphocyte response. This is a very important cell for the immune system. with long-term immunological memory and helps generate antibodies.

The study was conducted on more than 500 healthcare workers, assessing the level of antibodies and T-cell counts after two doses of Pfizer vaccine with a short interval between two doses (3-4 weeks, average 24 days) and long (6-14 weeks, average 70 days).

The study results showed that, for the group with a long injection interval, the antibody concentration decreased significantly between the first and second dose. In particular, the concentration of neutralizing antibodies against the Delta variant produced was worse after a single dose and was not maintained in the period before the second dose.

However, T cells were well maintained between the first and second doses. After two doses of the vaccine, neutralizing antibody levels doubled. The longer interval between two shots of the vaccine leads to higher levels of neutralizing antibodies after the second dose, helping the body fight off the Delta variant and other variants.

"Regardless of the vaccination schedule, research shows that antibody and T-cell levels vary significantly from individual to individual. Outcomes depend on genetics, underlying health conditions and personal history. exposed to Covid-19 and other viruses," the doctor said.

There is currently no official recommendation from the World Health Organization (WHO), the US Centers for Disease Control (CDC) or the National Immunization Committees for one booster shot. after completing the standard vaccination schedule with two doses of vaccine.

The protective effect of the vaccine is up to 6-12 months. In fact, those who are seriously ill hospitalized and die from Covid-19 are people who have not been vaccinated. In an effort to accelerate the Covid-19 vaccination campaign and vaccine resources are limited, the vaccine is still recommended according to the standard vaccination schedule. WHO will consider considering the third dose of Covid-19 vaccine for groups of people with weakened immune systems, including organ transplant recipients, people being treated for cancer, leukemia, HIV-infected people, etc. .

People who have had two doses of the Covid-19 vaccine, depending on the country and local regulations, can participate in many of the activities you did before the pandemic. However, when herd immunity has not been achieved and to maximize the ability to protect the body from Delta variant as well as prevent the spread of the virus to others, we need to take measures to keep distance from people. as well as wearing a mask.

Post a Comment

0 Comments