According to the Ministry of Health, in normal cases, 2 doses of AstraZeneca vaccine should be given at an interval of 8 weeks for good immunity.
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On September 13, a leading representative of the Central Institute of Hygiene and Epidemiology (Ministry of Health) said that according to the latest instructions of the vaccine manufacturer AstraZeneca, the interval between two injections increased from 4 weeks to 8-12. weeks to increase immune response rates. Under normal circumstances, this vaccine should be given at an interval of 8 weeks for good immunity.
However, in Vietnam, for risk groups and epidemic areas, due to the urgent need to complete the 2nd dose soon to protect people who have received the 1st dose, some localities have recently administered the 2nd dose of the vaccine. Apply for AstraZeneca earlier than recommended, with a gap of at least 4 weeks. In Official Dispatch No. 255/SYT-NYV dated July 22, 2021, Hanoi Department of Health also noted: For AstraZeneca vaccine, ensure a gap of at least 8 weeks between 2 doses; In some special cases, it is necessary to complete 2 doses early, then the 2nd injection can be performed after at least 4 weeks.
Previously, on September 12, the Department of Health of Ho Chi Minh City sent an official letter to the Ministry of Health requesting consideration and approval to shorten the interval between two doses of AstraZeneca vaccine from 8 to 12 weeks to at least 6 weeks in order to accelerate the progress of covering cape 2 in the city.
As of the afternoon of September 13, the Ministry of Health has not yet issued an official guideline on adjusting the injection interval to 4 weeks as suggested by Ho Chi Minh City.
Doctor Truong Huu Khanh, an infectious disease expert in Ho Chi Minh City, said: In the scientific research document of the AstraZeneca vaccine, the manufacturer instructs the time to inject 2 doses 4 weeks apart is just right. For better immunity, the interval is from 8 to 12 weeks. The manufacturer also clearly notes that in the epidemic area, it is recommended to inject early, the interval between 2 injections is 4 weeks. Therefore, Ho Chi Minh City recommends 6 weeks of injection and can also apply for 4 weeks.
“You have to cover 2 noses early to open the door and ensure safety. If you wait for up to 8 weeks, how can you ensure the safety of the people, not to mention that you may get infected while waiting. In addition, in principle, the injection must be completed 14 days later to create immunity, “said Dr. Khanh.
Instructions for combination injections
According to the Ministry of Health, to implement the Covid-19 vaccine strategy, Vietnam has so far received many vaccines manufactured using different technologies such as: vector technology (AstraZeneca, Sputnik V), technology mRNA technology (Pfizer, Moderna), inactivation technology (Sinopharm, Hayat-Vax).
Recently, due to the scarcity of vaccines, many countries have researched and used injection courses combining 2 vaccines with the same technology or different production technology, based on the type of vaccine available at each time. .
In Vietnam, stemming from the actual situation, the need to use it for the purpose of increasing coverage, and injecting early and on time to prevent epidemics, on September 8, the Expert Advisory Council on the use of vaccines of the Ministry of Health. Health has met and made recommendations: In case of force majeure when the supply Covid-19 vaccine If the 1st dose is not enough for the 2nd dose, another vaccine can be used to inject the 2nd dose as follows:
If you get 1st dose of AstraZeneca, you can get 2nd dose of Pfizer or Moderna. If you inject 1 Moderna, you can inject 2 Pfizer production and vice versa. The combination injection must have the consent of the person being injected.
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According to information on the official website of AstraZeneca Pharmaceutical Company, the Covid-19 vaccine AstraZeneca has been licensed for conditional circulation or for emergency use as a two-dose regimen 4 – 12 weeks apart for adults aged 4 to 12 weeks. 18 and older. Also on this website, the AstraZeneca vaccine information section contains a recommendation from the World Health Organization’s (WHO) Strategic Advisory Group on Immunization (SAGE) that the interval between two AstraZeneca injections should be between 8 – 12 weeks. This gap has been shown in clinical trials to be safe and most effective in preventing symptomatic Covid-19.
AstraZeneca’s website also posted a study by the University of Oxford (UK), which co-researched and developed this vaccine, which said that if the interval between two doses of AstraZeneca was extended up to 45 weeks, the anti- may be 4 times higher than the 12-week interval. This demonstrates that longer vaccination intervals are not detrimental but can also induce stronger immunity.
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Source: Thanh Nien Newspaper