Since the start of the COVID-19 virus, the world has been exposed to many strains of the virus, from the initial strain from Wuhan, China, to the alpha delta strain and the latest strain, the Omikron strain. Sub BA.1, BA.4 and BA.5
In 2020-2022, mRNA vaccines are the primary defense around the world for COVID-19 protection. But when the virus mutates into many strains Scientists and medical professionals have developed a bivalent vaccine, or bivalent vaccine, to allow the body of a vaccinated person to produce antibodies to respond to multiple strains of the virus.
What is Bivalent Vaccine?
The two-strain vaccine contains the mRNA genetic material of the COVID-19 virus. Half the original strain (Wuhan-Hu-1) and half the mRNA of the COVID omikron strain. in which the mRNA part of the omicron strain Vaccine manufacturers currently use genetic material from different subspecies, either BA.1 or BA.4, BA.5, depending on the company’s plans and the omikron strains prevalent in the vaccinated country.
While traditional mRNA vaccines only contain ingredients from the original COVID strain, the efficacy against Omikron strains is low. The second-generation vaccine, the bivalent vaccine, will provide better protection against all strains of COVID.
In late August 2022, the US Food and Drug Administration (FDA) announced the approval of both Moderna and Pfizer bivalent vaccines, which can be administered either as a second booster at least two months after the first booster dose, or as a second booster dose. It can be given as a booster shot after full vaccination. Moderna will be given to people age 18 and older, while Pfizer can be given to children age 12 and older before it announces that children age 5 and older can be vaccinated. after
Is Bivalent Vaccine More Effective?
The US FDA analyzed data from a group of 600 people ages 18 and older into two groups:
- Group 1: Complete 2 doses > Original Moderna Vaccine (Booster 1) > Original Moderna Vaccine (Booster 2)
- Group 2 Complete 2 doses > Original Moderna (Booster 1) > Moderna Bivalent (Booster 2)
Both groups received a second booster dose at least 3 months after receiving the first booster dose. The results of the data analysis showed that after 28 days after the second injection of the booster needle, The immune response to omiconron BA.1 in those vaccinated with bivalent was better than those vaccinated with first-generation mRNA or monovalent vaccines.
The efficacy of Pfizer’s Bivalent Vaccine was similarly tested. It analyzed data from a group of about 600 people aged 55 and older.
- Group 1: Complete 2 doses of vaccine > Original Pfizer Vaccine (Booster 1) > Original Pfizer Vaccine (Booster 2)
- Group 2: Complete 2 doses > Original Pfizer Vaccine (1st Dose) > Pfizer Bivalent (2nd Dose)
Both groups received the second booster vaccine approximately 5-13 months after the first dose. Data analysis revealed that 1 month after the second booster dose The immune response to the BA.1 ommicron strain of those vaccinated with bivalent was more responsive than those vaccinated with monovalent mRNA strains.
As for safety and side effects, it was found that Bivalent vaccines have side effects that are quite similar to first-generation mRNA vaccines. is that the vaccinated person has pain, redness and swelling at the vaccination site. Fatigue, headache, muscle pain, joint pain, chills, swollen lymph nodes on the arm where the vaccine was injected. including nausea, vomiting, and fever
However, it is difficult to measure vaccine efficacy because of many limitations. Both from the self-testing process that has many phases, both animal and human tests. Due to the rapidly changing disease situation, both Pfizer and Moderna had to use comparative immunotherapy methods instead.
Will Thailand be able to use the Bivalent Vaccine?
The United States, which was the first country in which Bivalent was vaccinated, has now extended the new generation of vaccines to young children. Moderna’s bivalent has been approved in 38 countries, and Pfizer’s bivalent has been approved in 35. country, according to information from the website covid19.trackvaccines.org
for Thailand The government has no signs of bringing in the 2-strain vaccine. On December 23, 2022, Dr. Tares Krassanairawiwong From the Department of Disease Control, it is recommended that people get the fourth dose of vaccination because it can prevent more severe symptoms and deaths. along with statingCurrently available vaccines are sufficient. There is no need to wait for the new generation of Bivalent vaccines.
Although the Department of Disease Control stated that Thailand has a slower trend of COVID-19 infections, the Bivalent vaccine may be important, especially when China announced the country’s reopening on Jan. 8 and began to attract some Chinese tourists. gradually entered Thailand
Many countries have imposed screening measures for COVID-19. with Chinese tourists Including the United States, which is concerned that information about the spread of COVID-19 From the Chinese side, the information is not transparent because it provides insufficient information on the number of domestic infections and no information on the strains that are currently prevalent in China.
Lack of information on strains of COVID-19 In China, this makes the bivalent vaccine even more important as it offers better protection against the Omikron strain than the first-generation booster vaccine, especially to Thailand, a major destination for Chinese tourists.
However, on various social media platforms, they have come out to demand that the Thai government import Bivalent vaccines and impose strict measures on Chinese tourists like many countries do, but there is still no sign that the government will bring in two strains of vaccines, although the country Neighbors like Malaysia and Singapore are already using Bivalent. It is uncertain when Thailand will use this Bivalent vaccine, but probably not anytime soon.
refer – Pfizer, US FDA, Ministry of Public Health, BBC, TIME
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