Is influenza vaccine inactivated or inactivated？ Trivalent or tetravalent？
Original Tencent medical code
Many people have taken or are planning to take a shot of flu vaccine, but they may be blindsided as soon as they come to the vaccination clinic-how can there be so many kinds of flu vaccines?
● There is "inactivation" and "inactivation";
● There are "injections" and "nasal sprays";
● There are "trivalent" and "tetravalent";
● There are "cracking" and "subunits".
And each kind, there are different brands and different prices of products. In another hospital, I found that there are different choices.
I just want to get a good vaccine. Why is it so difficult and brain-wasting?
How to choose the flu vaccine?
For the flu season in 2023/2024, there are the following flu vaccines in mainland China [4]:
● Children from 6 months to 3 years old: trivalent inactivated influenza vaccine and tetravalent inactivated influenza vaccine are available;
● Children and adults over 3 years old: trivalent inactivated influenza vaccine and tetravalent inactivated influenza vaccine are available;
● Children aged 3 to 17: There is also a trivalent live attenuated influenza vaccine.
Is it a little winding? It doesn’t matter, a table shows clearly:
At present, influenza vaccines that need intramuscular injection are all "inactivated" vaccines (commonly known as "dead vaccines").
The "dead" vaccine does not contain live viruses, and vaccination will not make people get the flu. Generally, sufficient immunity is generated after 2 to 4 weeks of inoculation.
The flu vaccine that needs nasal spray is an attenuated live vaccine, which is suitable for people aged 3 to 17.
Studies have shown that nasal spray can produce nasal mucosal antibodies in as little as 3 days [5].
Therefore, for those children who are particularly afraid and resistant to "injection" or have skin diseases in their upper arms and no suitable injection site, "nasal spray" vaccine seems to be a more friendly choice.
However, those children who have immunodeficiency diseases, received other attenuated live vaccines (such as measles vaccine, chicken pox vaccine, etc.) within one month, or have severe rhinitis, nasal congestion, runny nose and other symptoms are not suitable for vaccination.
Of course, no matter inactivation or inactivation, it has a good protective effect and can be selected as needed.
The "price" in the vaccine name does not mean "price", but refers to the type of the same pathogen.
For example, "trivalent pneumonia vaccine" can prevent infections caused by 13 kinds of pneumococci; The "9-valent HPV vaccine" can prevent infections caused by 9 kinds of HPV (human papillomavirus).
The higher the "price", the more types of pathogens are covered, and the wider the infection can be prevented (many people will mistakenly write it as "intermediary" and "rank", which is wrong).
Influenza viruses that can infect humans and cause widespread epidemic are mainly H1N1 and H3N2 subtypes of influenza A and Victoria and Yamagata strains of influenza B..
The tetravalent influenza vaccine can prevent one more influenza virus (Yamagata strain B) than the trivalent influenza vaccine.
At the end of September this year, the World Health Organization (WHO) believed that since March 2020, Yamagata strain of influenza B had not been monitored and isolated worldwide [6].
This may be related to the epidemic situation in COVID-19 in recent three years and its prevention and control, especially the changes in people’s living habits and behaviors (such as wearing masks, reducing travel and increasing social distance) [7].
However, the fact that the virus has not been detected for the time being does not mean that the virus has "completely disappeared" and there is still the possibility of making a comeback in the future. As a precaution, WHO continues to provide recommendations on the composition of tetravalent influenza vaccine [6].
Therefore, for this year, playing 3 prices is enough; At 4 prices, you won’t lose. When choosing a flu vaccine, you don’t have to worry about the specific price.
Some people may have found that the same "inactivated" vaccine is also divided into "split" and "subunit". What’s the difference?
In fact, inactivated vaccine is to completely "kill" pathogens (such as influenza virus), take their "corpses" and make them into vaccines after processing.
Some inactivated vaccines use whole bodies, such as inactivated hepatitis A vaccine, rabies vaccine and COVID-19 vaccine.
The "split" vaccine is to split, disintegrate, filter and purify the dead virus, which greatly reduces the adverse reactions of the vaccine [8].
The "subunit" vaccine goes a step further, removing the internal protein of the virus and only extracting some components (such as neuraminidase and hemagglutinin of influenza virus), with less impurities [9] and better safety.
However, at present, the production of "subunit" influenza vaccine is relatively small and the price is more expensive.
The Technical Guide for Influenza Vaccine Vaccination in China issued by China Center for Disease Control and Prevention indicates that people who can vaccinate vaccine products of different types and manufacturers can voluntarily vaccinate any kind of influenza vaccine, and there is no prior recommendation [4].
In other words, any kind of flu vaccine can provide us with good protection. What is important is to vaccinate in time, not to choose or wait.
May each of us spend this coming winter safely and healthily!
Audit expert: Wang Qing
Chief physician, Department of Immunization Planning, Xicheng District Center for Disease Control and Prevention, Beijing
references
1.https://wjw.beijing.gov.cn/bmfw_20143/jkzs/mzyq/202310/t20231024_3285888.html
2.http://wjw.jiangsu.gov.cn/art/2023/10/27/art_49513_11054944.html
3.https://ivdc.chinacdc.cn/cnic/zyzx/lgzb/202310/t20231026_270329.htm
4. China Center for Disease Control and Prevention. Technical Guide for Influenza Vaccination in China 2023-2024.
5.Barría Maria Ines, Luis G J , Cheryl S , et al.Localized mucosal response to intranasal live attenuated influenza vaccine in adults.[J].Journal of Infectious Diseases, 2013(1):115-124.DOI:10.1093/infdis/jis641.
6.https://www.who.int/publications/m/item/recommended-composition-of-influenza-virus-vaccines-for-use-in-the-2024-southern-hemisphere-influenza-season
7.Koutsakos, M., Wheatley, A.K., Laurie, K. et al. Influenza lineage extinction during the COVID-19 pandemic? . Nat Rev Microbiol 19, 741–742 (2021). https://doi.org/10.1038/s41579-021-00642-4
8. Wang Lijie, Huang Weijin, Wang Youchun. Progress in research and development of universal influenza vaccine [J]. China Food and Drug Administration, 2023,05:18-23.
9. Yang Xiaoming, Gao Fu, Yu Yongxin, et al. Contemporary new vaccines [M]. Beijing: Higher Education Press, 2020.
* Produced by Tencent Medical Content Team
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