7價的肺炎雙球菌疫苗解釋了pneumococcal serotype 19A的盛行
競爭壓力改變族群
19A容易造成invasive disease and resistance
Explaining the Increase in Pneumococcal Serotype 19A
Heptavalent conjugated pneumococcal vaccine is associated with increased carriage of pneumococcal serotype 19A strains.
Heptavalent conjugated pneumococcal vaccine (PCV-7) was incorporated into routine U.S. childhood vaccination schedules in 2001. Since then, reports have surfaced about outbreaks or clusters of children with invasive Streptococcus pneumoniae serotype 19A disease (JW Pediatr Adolesc Med May 23 2007 and JW Infect Dis Nov 7 2007). This serotype is known for its tendency to cause invasive disease and its resistance to antibiotics. Is the increase in serotype 19A disease a result of natural fluctuation in serotypes or introduction of the PCV-7 vaccine? To find out, investigators in the Netherlands conducted a post hoc analysis of data from a randomized study of PCV-7 dosing schedules conducted before routine use of the vaccine.
Researchers compared the cumulative proportion of new nasopharyngeal S. pneumoniae serotype 19A isolates in 948 children randomized to one of three PCV-7 vaccination schedules: no PCV-7 vaccination; two doses of PCV-7 at ages 2 and 4 months; or three doses at ages 2, 4, and 11 months. Nasal swabs for S. pneumoniae culture and serotyping were collected at age 6 weeks (baseline) and at ages 6, 12, 18, and 24 months. At baseline, <1% of infants in each group tested positive for serotype 19A. By age 24 months, the proportion of children who tested positive for 19A colonization was significantly higher in the three-dose group than in the unvaccinated group (16.2% vs. 9.2%). The proportion in the two-dose group was 13.2%. Antibiotic use and resistance did not differ among the three groups.
Comment: The increase in serotype 19A seems to represent serotype replacement resulting from the reduction in colonization of vaccine serotypes. These study results underscore the need to rapidly incorporate the new PCV-13 vaccine —which includes serotype 19A (JW Pediatr Adolesc Med Mar 24 2010) — into our vaccination schedules and continue to examine the changing epidemiology of serotype replacement in our practice areas.
— Peggy Sue Weintrub, MD
Published in Journal Watch Pediatrics and Adolescent Medicine September 22, 2010
Citation(s):
van Gils EJM et al. Pneumococcal conjugate vaccination and nasopharyngeal acquisition of pneumococcal serotype 19A strains. JAMA 2010 Sep 8; 304:1099.
* Original article (Subscription may be required)
* Medline abstract (Free)
19A容易造成invasive disease and resistance
Explaining the Increase in Pneumococcal Serotype 19A
Heptavalent conjugated pneumococcal vaccine is associated with increased carriage of pneumococcal serotype 19A strains.
Heptavalent conjugated pneumococcal vaccine (PCV-7) was incorporated into routine U.S. childhood vaccination schedules in 2001. Since then, reports have surfaced about outbreaks or clusters of children with invasive Streptococcus pneumoniae serotype 19A disease (JW Pediatr Adolesc Med May 23 2007 and JW Infect Dis Nov 7 2007). This serotype is known for its tendency to cause invasive disease and its resistance to antibiotics. Is the increase in serotype 19A disease a result of natural fluctuation in serotypes or introduction of the PCV-7 vaccine? To find out, investigators in the Netherlands conducted a post hoc analysis of data from a randomized study of PCV-7 dosing schedules conducted before routine use of the vaccine.
Researchers compared the cumulative proportion of new nasopharyngeal S. pneumoniae serotype 19A isolates in 948 children randomized to one of three PCV-7 vaccination schedules: no PCV-7 vaccination; two doses of PCV-7 at ages 2 and 4 months; or three doses at ages 2, 4, and 11 months. Nasal swabs for S. pneumoniae culture and serotyping were collected at age 6 weeks (baseline) and at ages 6, 12, 18, and 24 months. At baseline, <1% of infants in each group tested positive for serotype 19A. By age 24 months, the proportion of children who tested positive for 19A colonization was significantly higher in the three-dose group than in the unvaccinated group (16.2% vs. 9.2%). The proportion in the two-dose group was 13.2%. Antibiotic use and resistance did not differ among the three groups.
Comment: The increase in serotype 19A seems to represent serotype replacement resulting from the reduction in colonization of vaccine serotypes. These study results underscore the need to rapidly incorporate the new PCV-13 vaccine —which includes serotype 19A (JW Pediatr Adolesc Med Mar 24 2010) — into our vaccination schedules and continue to examine the changing epidemiology of serotype replacement in our practice areas.
— Peggy Sue Weintrub, MD
Published in Journal Watch Pediatrics and Adolescent Medicine September 22, 2010
Citation(s):
van Gils EJM et al. Pneumococcal conjugate vaccination and nasopharyngeal acquisition of pneumococcal serotype 19A strains. JAMA 2010 Sep 8; 304:1099.
* Original article (Subscription may be required)
* Medline abstract (Free)
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