The difference between attenuated and inactivated hepatitis A vaccines

Babies need to receive some vaccines every month after birth, which is very important for the baby's health. When vaccinating with hepatitis A vaccine, it is mainly divided into inactivated hepatitis A vaccine and live attenuated vaccine. What is the difference between these two vaccines? It should be said that these two vaccines have their own advantages and disadvantages. Under the guidance of professionals, you can choose the type of vaccine according to your child's situation.

There are two main types of hepatitis A vaccines on the market: inactivated hepatitis A vaccine and live attenuated hepatitis A vaccine. Due to different preparation principles, there are differences in effectiveness and safety. Compared with live attenuated vaccines, inactivated vaccines have better stability, while live attenuated hepatitis A vaccines are relatively cheap. So, what is the difference between attenuated and inactivated hepatitis A vaccines?

【Attenuated Hepatitis A Vaccine】

Live vaccines or attenuated live vaccines are made by using artificial directed mutation methods or by screening out live microorganisms with reduced virulence or essentially non-toxicity from nature.

To put it simply, the vaccine is alive, but it is generally made by culturing and breeding "virus or mycoplasma strains that are non-toxic or have very low virulence but highly immunogenic." It can not only produce protective antibodies, but also enhance the activation, recognition, and phagocytosis capabilities of cellular immunity.

Commonly used live vaccines include Bacillus Calmette-Guérin (BCG, tuberculosis), measles vaccine, polio vaccine (polio), etc. After vaccination, the virus has the ability to grow and reproduce in the body, which is close to natural infection and can stimulate the body's lasting immunity to pathogens.

Live vaccines require smaller doses and provide longer duration of immunity. The immune effect of live vaccines is better than that of dead vaccines. For example: varicella vaccine is a live attenuated vaccine, and leprosy and mumps vaccines are both live vaccines.

Advantages of live attenuated hepatitis A vaccine

1. The number of vaccinations required is relatively small. Some live attenuated vaccines only require one vaccination, similar to the process of natural infection;

2. After staying in the human body for a period of time, it can proliferate and produce a large number of antigens, thus producing a good immune response effect;

3. The immune effect is relatively strong, which can not only promote the formation of systemic immunity, but also produce local immunity;

4. Vaccination can be carried out through natural infection, which will have a better immune effect, such as oral attenuated live polio vaccine;

[Disadvantages of live attenuated hepatitis A vaccine]

1. There is a potential risk of virulence reversion in the human body; it may cause potential infection or spread;

2. Vaccines may be contaminated with factors that are harmful to the human body;

3. Live attenuated vaccines are unstable and difficult to store and transport; viruses may interfere with immunity.

【Inactivated Hepatitis A Vaccine】

It is made by selecting bacteria, viruses, rickettsia, spirochetes, etc. with good immunogenicity, culturing them artificially, and then killing them by physical or chemical methods. This vaccine loses its ability to reproduce but retains its immunogenicity. After entering the human body, killed vaccines cannot grow and reproduce, and their stimulation on the body is short-lived. To obtain lasting immunity, repeated vaccinations are required. This is why the inactivated hepatitis A vaccine needs to be given twice.

In layman's terms, an inactivated vaccine is a killed virus. When it is injected into the human body, it will not cause illness but will enable the body to produce antibodies to resist viral invasion.

[Advantages of inactivated hepatitis A vaccine]

1. The manufacturing process is simple, and pathogenic microorganisms are directly obtained by artificial reproduction and used as antigens after inactivation;

2. Can kill any other biological factors that may become pollutants;

3. Inactivated vaccines are relatively stable and easy to store and transport.

[Disadvantages of inactivated hepatitis A vaccine]

1. The effective antigenic determinants may be damaged or changed during the inactivation process;

2. The immune effect produced is short-lived and no local antibodies are produced;

3. May produce toxicity or potential adverse immune responses to the body;

4. It requires multiple injections, requires a relatively large amount of antigen, and is relatively costly.