Why do you need the 4th dose of vaccine?

10/06/2022 10:53 GMT+7

What are the benefits of getting the 4 vaccine?

Like many vaccines, people who have received their full and timely Covid-19 vaccinations will have the best protection. However, with the appearance of the Omicron variant and the gradual decrease in post-vaccination protection over time (especially for some at-risk groups). Therefore, in order to strengthen immunity against Covid-19 for those who have been vaccinated, the Ministry of Health has directed the people to give the people a second booster vaccination against Covid-19 (nose 4).

According to HCDC, in the past time, Covid-19 vaccines have shown to be effective in protecting people in reducing the possibility of serious illness, avoiding hospitalization, and even preventing death from Covid-19, especially especially in those who have had a booster shot.

Around the world, a number of countries have implemented additional booster doses in addition to the first booster dose (shot 3). However, data on the effectiveness of these additional booster doses are sparse and particularly limited on the duration of additional protection.

Why do you need the 4th dose of the vaccine?

According to a synthesis from the World Health Organization (WHO), there are currently 7 studies on the effectiveness of 4 doses of Covid-19 vaccines. In which, 6 studies from Israel and 1 study from Canada. All were conducted during a time when Omicron was the most common circulating variant around the globe. Although the studies varied in design and population, most rated the four doses of Covid-19 vaccine as effective.

Specifically, of the 7 studies investigating the use of doses of the Covid-19 mRNA vaccine, 2 were conducted on healthcare workers in Israel. The results of the first study showed that the vaccine triggered a strong immune response (both IgG and neutralizing antibodies) increased 9 or 10 times and the vaccine caused no side effects. large for the study object.

The second study examined post-vaccination Covid-19 infections among healthcare workers who received 3 doses of Pfizer-BioNTech vaccine and compared it with those who received 4 doses of these vaccines.

Results showed that in those who received dose 4 there was a reduction in the incidence of Covid-19 after vaccination compared with rates observed after only 3 doses of this vaccine.

Of the remaining five studies, all of which were conducted in people over 60 years of age, excluding those with previous Covid-19 infections, four doses of the vaccine were found to be effective.

Among them, the researchers found that the rate of severe Covid-19 infection one month after the fourth dose was 3.5 times lower than in the three-dose group.

The last study done in Canada showed that with each additional dose, vaccine efficacy increased for severe disease. Specifically, absolute vaccine efficacy was 82% (95% CI: 75-88%) measured more than 84 days after the third dose and 92% (95% CI: 87-95%) for recipients of the 4th dose. .

Who needs the 4th dose of vaccine?

According to the US Centers for Disease Control and Prevention (US CDC) it is recommended that 4 booster doses of Pfizer-BioNTech or Moderna Covid-19 vaccines be given at least 4 months after the first booster dose for subjects including adults and children. older than 50 years old; People 12 years of age and older with moderate or severe immunodeficiency.

Accordingly, on May 9, 2022, the Ministry of Health also issued Document No. 2357/BYT-DP directing the implementation of the 2nd booster dose of Covid-19 vaccine (nose 4) as follows:

Injected subjects: People aged 50 years or older, people 18 years of age or older with moderate to severe immunodeficiency, people aged 18 years or older in the high-risk group for exposure to Covid-19: medical staff economy, frontline officials, industrial park workers.

Vaccines used: mRNA vaccine (manufactured by Pfizer or Moderna), vaccine produced by Astra Zeneca, vaccine of the same type with dose 3.

Interval: At least 4 months after the 3rd dose.

People who have contracted Covid-19 after injection 3: Postponed 3 months after contracting Covid-19.

According to the Ministry of Health, the Covid-19 vaccine is the most important key in epidemic prevention and control and is the foundation for safe and effective adaptation. Therefore, each of us should vaccinate according to the guidelines of the health industry.

Khanh Chi