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Effects of pneumococcal vaccination on tonsillo-pharyngitis and upper respiratory tract flora
Insights
The 14-valent pneumococcal vaccine showed varied effects on upper respiratory infections in children. While reducing infections in older children, it increased tonsillitis in younger ones and altered streptococcal carriage.
Area of Science:
- Pediatric infectious diseases
- Vaccinology
- Microbiology
Background:
- Pneumococcal vaccines are crucial for preventing invasive pneumococcal disease.
- The impact of pneumococcal vaccines on other respiratory pathogens and carriage is less understood.
- Upper respiratory tract infections (URTIs) and streptococcal carriage are common in young children.
Purpose of the Study:
- To investigate the effect of a 14-valent pneumococcal vaccine on URTIs and beta-haemolytic streptococci carriage in children aged 0.5-5 years.
- To explore age-specific responses to pneumococcal vaccination regarding respiratory infections and bacterial carriage.
Main Methods:
- A double-blind, prospective study involving 405 children aged 0.5-5 years.
- Participants were randomized to receive either the 14-valent pneumococcal vaccine or a placebo.
- Outcomes assessed included incidence of URTIs, acute tonsillitis, and carriage of beta-haemolytic streptococci (specifically Group A and C).
Main Results:
- In children vaccinated under 2 years, acute tonsillitis was more frequent in vaccinees (p<0.01).
- In children vaccinated over 2 years, acute tonsillitis and total URTIs were significantly reduced (p<0.01).
- Vaccination increased asymptomatic carriage of Group A streptococci in children aged 2-5 years (p<0.01) but decreased Group C streptococci carriage (p<0.05).
Conclusions:
- The 14-valent pneumococcal vaccine demonstrates age-dependent effects on URTIs and streptococcal carriage.
- Unexpected findings suggest potential non-specific immune modulation or cross-protection mechanisms.
- Further research is needed to elucidate the mechanisms behind these observed effects.
Abstract:
The effect of a 14-valent pneumococcal vaccine on upper respiratory tract infections and carriage of beta-haemolytic streptococci was studied in a double-blind prospective study of 405 children 0.5-5 years of age. In the children under 2 years of age at vaccination, the cases of acute tonsillitis were more frequent among the vaccinees than among the controls (p less than 0.01). In contrast, among the children over 2 years of age at vaccination, fewer episodes of acute tonsillitis were reported among the vaccinees than among the controls (p less than 0.01). In the older age group, the total rate of upper respiratory tract infections was also significantly reduced. Similarly, an increase in asymptomatic carriage of group A streptococci was registered in children vaccinated at 2-5 years of age (p less than 0.01). Inversely, the carriership of group C streptococci diminished among the vaccinated children (p less than 0.05). Some possible mechanisms underlying these unexpected findings, including non-specific mitogenic features and cross-protection due to antigenic similarities, were explored.