＂Live vaccine＂ and ＂dead vaccine＂, are you still confused？

Every time I get a vaccine, I encounter live attenuated vaccine, inactivated vaccine, recombination vaccines, vector vaccine, etc., which makes people confused and difficult to choose. So, how can I know them quickly and choose the most suitable one? Today, Miss CDC will first talk about the most basic vaccine classification, "live vaccine" and "dead vaccine".

01

What is a live vaccine?

"Live vaccine" usually refers to "attenuated live vaccine", which allows bacteria or viruses to be repeatedly passed down until the pathogenicity is reduced to not make people sick, but the activity still exists. In other words, it can stimulate the body to produce humoral immunity and cellular immunity, similar to a mild natural infection.

At present, there are BCG vaccine, measles vaccine, chickenpox vaccine, rotavirus vaccine, live attenuated herpes zoster vaccine and live attenuated influenza vaccine on the market.

Advantages of "live vaccine":

A few doses of inoculation can produce a good immune response;

In addition to injection, it can also be immunized by natural infection such as oral administration and nasal spray;

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The immune effect is more lasting.

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Disadvantages of "live vaccine":

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Circulating antibodies (such as maternal antibodies) in the recipients can weaken or fail the immune effect of attenuated live vaccine;

It is not suitable for patients with immunodeficiency or patients undergoing immunosuppressive therapy.

02

What is a dead vaccine?

Dead vaccine refers to inactivated vaccine, polysaccharide vaccine, subunit vaccine and split vaccine. "Dead vaccine" includes many processes. Take inactivated vaccine as an example. It inactivates bacteria or viruses by heating or using chemicals, and then makes vaccines after purification. Therefore, there are no living bacteria and viruses in the "dead vaccine", and it is impossible to cause infection to people.

Inactivated polio vaccine, rabies vaccine, hepatitis B vaccine and inactivated Japanese encephalitis vaccine all belong to "dead vaccines".

Advantages of "dead vaccine":

Relatively stable, usually not affected by circulating antibodies (such as blood products, maternal antibodies, etc.) in the recipient;

Better safety, and will not cause infection of the recipient.

Disadvantages of "dead vaccine":

It is necessary to vaccinate many times and strengthen immunization to obtain better immune effect;

Generally, it can only be inoculated by injection.

03

How to choose a vaccine?

"Live vaccine" and "dead vaccine" have their own advantages and disadvantages. For healthy people, both vaccines are very safe and rarely have serious adverse reactions. If there are both attenuated live vaccine and inactivated vaccine to choose from, such as hepatitis A vaccine and Japanese encephalitis vaccine, we can comprehensively consider the inoculation times, inoculation route and price.

References:

Sun Xiaodong, Chen Dong. Super practical handbook of baby vaccination [M]. Shanghai Jiaotong University Press, 2022.

Contributed by Lin Wanjing

Original title: "Live vaccine" and "dead vaccine", are you still stupid and unclear? 》

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