What are the attenuated vaccines?

After a child is born, he or she needs to go to the hospital to get several vaccines. Parents must understand the relevant knowledge about children's vaccinations, get the vaccines at the right time, and pay attention to relevant matters before and after the vaccination. In addition, adults also often need to get some vaccines, such as rabies vaccines after being scratched by cats and dogs. Many people have also been vaccinated with attenuated vaccines. So what are the current attenuated vaccines?

What are the advantages and disadvantages of attenuated vaccines?

advantage

1. Induce two immune responses: humoral immunity and cellular immunity. Some products can also induce mucosal immunity through natural infection, so that the body can obtain a wider range of immune protection.

2. The products use live microorganisms, which can act in the body for a long time and induce a stronger immune response.

3. Living microorganisms have the characteristic of re-proliferation. In theory, only one vaccination is needed to achieve a satisfactory immune effect.

4. It may cause horizontal transmission, expand the immune effect, and enhance the herd immunity barrier;

5. No need to add adjuvant;

6. The production process generally does not require concentration and purification;

7. Low price.

shortcoming

1. Generally, live attenuated vaccines retain a certain amount of residual virulence, which may induce serious diseases in some individuals (such as those with immunodeficiency).

2. Due to various reasons (such as genetic modification, etc.), live attenuated vaccines may experience "reversion to virulence".

3. It is a live microbial preparation, which may cause environmental pollution and cross infection.

4. Defective particles may interfere with the immune effect of the vaccine.

5. Analysis and evaluation of products is difficult.

6. The storage and transportation conditions are relatively high, such as cold chain.

Contraindications

1. General taboos

● Vaccination with live vaccines should be postponed for patients who have used immunoglobulin, immune globulin, or other passive immunization preparations within the past 4 weeks [1].

●The incubation period, prodromal period, onset period and recovery period of acute infectious diseases. People with a history of certain infectious diseases may not need to receive the corresponding vaccine as they have already acquired immunity after the illness.

● Vaccination should be postponed for people with fever (especially high fever), acute diseases, and severe malnutrition.

●People with allergic constitution, bronchial asthma, urticaria, thrombocytopenic purpura, or a history of food allergies should not be vaccinated with vaccines containing this allergen.

● Vaccination should be postponed for patients with active pulmonary tuberculosis, cardiac insufficiency, acute and chronic kidney disease, diabetes, hypertension, cirrhosis, blood system diseases, severe chronic diseases, active rheumatic diseases, severe suppurative skin diseases, etc.

2. Special taboos

●People with immunodeficiency, leukemia, lymphoma, malignant tumors, or those whose immune function is suppressed by the use of corticosteroids, alkylating agents, antimetabolites, radiotherapy, or splenectomy should not use live vaccines.

● Pregnant women, especially during pregnancy, should not use live vaccines.

●People who suffer from neurological diseases and mental illnesses such as epilepsy, hysteria, sequelae of encephalitis, convulsions, or have a history of such diseases are prohibited from receiving the Japanese encephalitis vaccine, diphtheria, pertussis and tetanus vaccine, and meningococcal polysaccharide vaccine.

●After receiving the DTP vaccine, if there is a strong reaction such as collapse or shock, continuous screaming, body temperature over 40°C, convulsions or twitching, severe changes in consciousness, systemic or local neurological symptoms, allergic reactions, thrombocytopenia or hemolytic anemia, or other serious abnormal reactions, the subsequent injections should be stopped.

●People with eczema, suppurative otitis media or other serious skin diseases, or those with a positive tuberculin test should not receive BCG vaccination.

●Diphtheria toxoid and its mixed preparations are contraindicated for patients in the recovery stage of nephritis or chronic nephritis.