The effect of the fourth dose of BNT vaccine is revealed: reducing the risk of death from severe disease. "The validity period is too short" and may it become fatal?
Recently, the number of confirmed cases in Taiwan has “frequently exceeded 1,000,” revealing that epidemic prevention policies are gradually moving towards coexisting with the virus. However, people from all walks of life are worried that the protective power of the third dose will begin to expire in June, and there are calls for the administration of the “fourth dose”. Commander Chen Shizhong also said that he will discuss the latest vaccine policy direction on the 20th.
Is the “4th dose” necessary? Israel, which is known for its vaccination efficiency that is “unique in the world”, has pointed out through an observational study of 300,000 people that the fourth dose of the vaccine does have the effect of extending protection and avoiding severe mortality for elderly people over 60 years old. . But taking a long-term perspective, how long will vaccine protection last? Still an unanswered question.
Elderly Israelis’ death rate from severe illness and protective power exposed after taking “4th dose” of vaccine
The research team collected data from January 3 to February 18, 2022, when Israel was at the peak of the Omicron epidemic. The subjects were all elderly people over 60 years old, who had received the third dose of BNT vaccine at least 4 months ago, and had no symptoms of COVID-19 as confirmed by PCR screening.
The research team focused on observing the protection conferred by the fourth dose of BNT vaccine in 5 categories:
PCR screening positivity rate.
Rate of symptomatic infection.
Hospitalization rates.
Severity rate.
Mortality.
The changes in antibody concentration and protective power were observed from days 7 to 30 and from days 14 to 30 after the fourth dose. In addition, variables such as age, gender, place of residence and race were also included in the assessment.
The results showed that among the 340,402 people who received the fourth dose of the vaccine, the protection from days 7 to 30 was as follows compared with the protection from the third dose:
PCR screening positivity rate dropped by 44-47%.
The symptomatic infection rate dropped by 53-58%.
Hospitalization rates dropped by 59-74%.
The severe disease rate dropped by 50-74%.
Mortality rate reduced by 50-90%.
Are there any concerns about receiving the fourth dose of vaccine? Expert: The protection is more short-lived and may cause “immune paralysis”
The results of the study show that the fourth dose of BNT vaccine does increase protection for elderly people over 60 years old who received the third dose four months ago. However, a previous study published in the New England Journal of Medicine (NEJM) pointed out that compared with the third dose, the protection of the fourth dose of the vaccine is short-lived. Although it can also reduce the risk of moderate to severe disease, it also proves that it is less effective in confirming the diagnosis. The protective effect of the vaccine “weakened rapidly” on average after the 8th week of treatment.
There are still potential concerns about the fourth dose of the vaccine. For example, the European Medicines Agency (EMA) has raised whether too frequent vaccination will lead to a weakening of the immune response. In addition, some scholars believe that the fourth dose of the vaccine will have a huge impact on the human body’s immune system. The protection against future variants that may be too diverse will gradually decrease, causing “immune paralysis” in the human body.
Although mRNA vaccines such as Moderna and BNT vaccines are designed to combat the “spike protein” of the new coronavirus, Omicron is quite different from the original strain of the new coronavirus, that is, it has a large number of mutations in the spike protein. However, the fourth dose of the mRNA vaccine did play an role in inhibiting the toxicity of Omicron, especially in the elderly over 60 years old. Research shows that further observation is still needed to determine whether vaccination frequency and vaccine combination are long-term strategies for epidemic prevention.
Source:
Protection by a Fourth Dose of BNT162b2 against Omicron in Israel
Fourth Dose of BNT162b2 mRNA Covid-19 Vaccine in a Nationwide Setting
Further reading:
Is the “4th dose” effective against Omicron? Israeli study says benefits may be ‘minimal’
