The necessity of pneumococcal vaccination, these groups of people must understand

In order to enhance the ability to resist external viruses, we have been vaccinated with different types of vaccines since childhood, and pneumococcal vaccine is one of them. Many people have many questions about the pneumococcal vaccine. This article will give you some reference.

What are the dangers of pneumococcus?

Pneumococcus is a very common bacterium that lives in the human nasopharynx and spreads from the nasopharynx through respiratory droplets. In most cases, the carrier has no symptoms, but when the immune system is weakened, pneumococcus will emerge and destroy human health. Although this bacterium is named pneumonia, it can also cause common diseases such as meningitis, bacteremia and otitis media. According to the World Health Organization (WTO), 1.6 million people die from pneumococcal infection every year worldwide, of which 460,000 are infants and young children. In my country, pneumonia caused by pneumococcus is an important common disease in infancy and ranks first among the causes of death in hospitalized children. About 30,000 children die from pneumococcal infection every year. The elderly are also a high-risk group for pneumococcal infection due to their weakened immune function and the combination of multiple chronic diseases, and the mortality rate is relatively high.

Why should I get the pneumococcal vaccine?

The pneumococcal vaccine is designed to prevent pneumococcal infection and can significantly reduce the risk of death caused by acute respiratory infections. The world's first pneumococcal polysaccharide vaccine has reduced the hospitalization and mortality rates of patients by more than 50%. After the widespread vaccination of the 7-valent pneumococcal conjugate vaccine in the United States, the incidence of pneumococcal disease in children under 5 years old has also dropped by 94%. The World Health Organization has long listed childhood pneumococcal disease as a disease that requires "extremely high priority" vaccine prevention. Shanghai and Chengdu have included pneumococcal vaccines in the local immunization program vaccine list, and local residents who meet the vaccination conditions can get vaccinated for free or at a very low cost.

What types of pneumococcal vaccines are there?

Different types of pneumococcal vaccines are suitable for different age groups and susceptible populations. In order to explain which groups of people pneumococcal vaccines are suitable for, we have to start with the types of pneumococcal vaccines. Pneumococcal vaccines are mainly divided into pneumococcal polysaccharide vaccines and pneumococcal protein conjugate vaccines. There are currently two main pneumonia vaccines used in my country, namely 13-valent pneumococcal protein conjugate vaccines and 23-valent pneumococcal polysaccharide vaccines. The 13-valent and 23-valent here refer to the number of pneumococcal serotypes covered. More than 90 serotypes of pneumococci have been discovered. The 23-valent polysaccharide vaccine refers to the fact that the vaccine covers 23 common serotypes of pneumococci, while the 13-valent vaccine covers 13 serotypes. The difference between polysaccharide vaccines and conjugate vaccines lies in the different production processes. Polysaccharide vaccines use the immunogenicity of bacterial polysaccharides to purify the specific polysaccharides and make vaccines, so that the vaccinated body produces good immune antibodies. Protein conjugate vaccines combine polysaccharides with protein carriers. Although the process is more complicated, the immune effectiveness of the vaccine has also been improved, and it can also adapt to the population whose immune system is not yet fully developed.

Which groups of people are suitable for different types of pneumococcal vaccines?

Due to the difference in production process between polysaccharide vaccine and conjugate vaccine, the populations suitable for them are also different. Polysaccharide vaccine is generally suitable for infants and adults over 2 years old. It can produce good immune antibodies. However, the immune system of infants and young children under 2 years old is not yet fully developed, and the immunogenicity of polysaccharide vaccine is poor. They have almost no response to polysaccharide vaccine or the protection period is very short, so they are not suitable for polysaccharide vaccine. The protein conjugate vaccine process is more complicated, which can enable children under 2 years old to have an immune response to the vaccine. Therefore, for pneumococcal immunity, children over 2 years old, the elderly over 65 years old and other people susceptible to pneumococcus are recommended to be vaccinated with 23-valent pneumococcal polysaccharide vaccine. Children aged 3 months to under 2 years old are recommended to be vaccinated with 13-valent conjugate vaccine.

According to statistics, the 13-valent conjugate vaccine can cover about 88% of the invasive pneumococcal strains in children under 5 years old in my country, which can largely protect children under 5 years old from pneumonia caused by pneumococci. In addition, in June 2021, the US FDA approved the marketing of Pfizer's 20-valent pneumococcal conjugate vaccine (Prevnar 20) for adults aged 18 years and above to prevent invasive diseases and pneumonia caused by the 20 pneumococcal serotypes in the vaccine, but it has not yet been approved to enter the Chinese market.

In fact, pneumococcal disease is not terrible, and it can be effectively prevented through current vaccines. If your family or children have not yet received the pneumococcal vaccine, it must be completed as soon as possible to prevent it from happening.

Expert of this article: Yu Qinghong, Chief Physician of Rheumatology and Immunology Department, Zhujiang Hospital, Southern Medical University