"Invasive pneumococcal disease remains the most common invasive infection and poses a significant burden. Pneumococcal diseases, such as pneumonia or ear infection, pose significant burden. The new vaccine must cover conventional serotypes as well as newly introduced serotypes to manage the invasive pneumococcal infection and expect an additional reduction."

The introduction of the pneumococcal vaccine with the most serotypes in South Korea has brought attention to its preventive effects against pneumococcus and unmet needs for vaccines.

Given the availability of vaccines in the National Immunization Program (NIP), there is a heightened interest in the preventive effects of added serotypes.

Dr. Ki Wook Yun, Professor of the Department of Pediatrics and Adolescent Medicine at Seoul National University College of Medicine, emphasizes the importance of seeking ways to improve preventive effects in terms of society, given the additional effects of newly introduced drugs.

According to Dr. Yun, unlike viral infection, bacterial infection cannot be recovered by relying on immunity, requiring antibiotic treatment. Mortality in children has decreased compared to the past, but bacterial infection still needs considerable attention.

"Bacterial infection is one of the most burdening diseases in children. The prevalence decreased over time due to vaccine development and environmental improvement. Yet, the disease prevalence is higher than other diseases," Yun explained. "Not only children with immature immunity but seniors are prone to respiratory infections. Consequently, children and seniors are the primary patients for respiratory prevention and treatment."

Dr. Yun comments that given these factors, it is crucial to prevent infection through vaccination and to stop it from transitioning to severe stages.

Invasive pneumococcal disease remains the most common invasive infection and poses a high disease burden, so the importance of vaccination has been stressed.

"Bacterial identification is challenging for infections related to pneumococcus, leading to frequent use of antibiotics. Consequently, patients may experience aftermaths of the treatment," Dr. Yun stated. "Vaccines can prevent these issues and may alleviate antibiotic tolerance by reducing the volume of antibiotic use."

The government has included 13-valent and 15-valent pneumococcal vaccines in the NIP for children.

From a different view, it remains to be seen what impact of Prevenar 20, a recently approved vaccine containing 20 serotypes, will have.

Dr. Yun focuses on newly identified serotypes not included in the 13-valent vaccine as primary causes of infection.

"13-valent vaccine alone cannot prevent all serotypes, so vaccines that contain new serotypes may be necessary," Dr. Yun said. "New vaccine must cover conventional serotypes as well as newly introduced serotypes to manage invasive pneumococcal infection and expect additional reduction."

"Because Prevenar 20 also met non-inferiority to 13-valent vaccines, and it met immunogenicity requirements set by WHO at the fourth immunization, using the vaccine will likely be similar to the conventional vaccine," Dr. Yun added. "Additional serotypes can also offer disease prevention, so clinical benefits are expected."

"The 20-valent pneumococcal vaccine has established sufficient validity for the NIP…establishing mass immunity must be considered"

The remaining issue is whether the vaccine will be included in the NIP. While it offers broader prophylaxis than conventional vaccines, its introduction faces cost concerns due to the existing conventional vaccines already being part of the NIP.

Dr. Yun analyzes that considering foreign cases, disease burden, and as drug price increases, Prevenar 20 has established sufficient validity for the NIP.

"The 20-valent vaccine includes seven additional serotypes compared to conventional vaccines, potentially providing about 40-50% additional prevention against invasive pneumococcal infections. This suggests that the vaccine is more effective than existing ones," Dr. Yun said.

"About 70-80% of non-vaccine serotypes causing infections in South Korea are not included in existing vaccines," Dr. Yun stated. "About half of these are serotypes included in the 20-valent vaccine. Consequently, it may be inadequate to keep using existing vaccines."

Dr. Yun particularly emphasizes that to maximize the effects of the pneumococcal vaccine, increasing the vaccination rate for mass immunity must be considered.

The 13-valent conjugate vaccine previously achieved high vaccination rates and demonstrative high effectiveness. However, a drop in vaccination rates due to new vaccines not being included in the NIP may lead to an increase in invasive infections and pneumonia.

"Rather than expecting protection from individual vaccination, we must consider approaches generating society-wise preventive effects. Considering these views, there must be active measures to increase the vaccination rate with new vaccines such as Prevenar 20," Dr. Yun said.

Finally, Dr. Yun remarked, "Despite the significant burden of pneumococcal diseases, such as pneumonia or ear infection, a surveillance system has not been established in South Korea." Adding, "The Korea Disease Control and Prevention Agency (KDCA) must address these aspects and implement systematic improvements so that invasive pneumococcal diseases are not overlooked."