— New Data Tracks Serotype Epidemiology and Antimicrobial Resistance in China —
Bangkok, 18 March, 2009 – Pneumococcal disease-causing bacteria strains are changing and rates of resistance to commonly used antimicrobials (erythromycin and penicillin) are increasing according to new data from China presented today at the 7th International Symposium on Antimicrobial Agents and Resistance (ISAAR).
A study conducted in Beijing investigated the distribution of Streptococcus pneumoniae (S. pneumoniae) serotypes 6A, 6B and 6C in 1997 and from 2000 to 2007, in children with upper respiratory infections. The study also assessed the effect of antimicrobials (erythromycin and penicillin) on these strains.1
Eight-hundred and sixty S. pneumoniae isolates were collected during the study, of which 109 (12.7 per cent) expressed serogroup 6. Of these, type 6A, 6B and 6C were identified in 62 (56.9 per cent), 38 (34.9 per cent) and 9 (8.2 per cent) samples, respectively. The results found that there was a decrease in the rate of serotypes 6A, 6B and 6C between 1997 and 2007 (20.3 per cent to 8.8 per cent, respectively). The results also found that serotype 6 is now 100 per cent resistant to erythromycin in China.1
During the same time period, the proportion of serotype 19A isolates increased from 2.59 per cent in 2000-2001 to 20 per cent in 2006-2007 while the rate of serotype 19A among penicillin non-susceptible increased from 3.92 per cent in 2000-2001 to 26 per cent in 2006-2007.2
“These results demonstrate that the distribution of pneumococcal disease causing bacteria is evolving. Serotypes that were previously prevalent are now less prevalent, while antimicrobials that were once effective have little effect today,” said Dr. Yang, Beijing Children’s Hospital, affiliated to Capital Medical University, Beijing, China. “Understanding how pneumococcal disease-causing serotypes and the effectiveness of routinely-used treatments are evolving will allow us to better manage this disease.”
Pneumococcal disease claims approximately 1.6 million lives each year worldwide. Up to one million of these deaths are children less than five years of age.3 Moreover, five of the top 10 countries with the highest pneumococcal disease burden are found in Asia: Bangladesh, China, India, Indonesia and Pakistan.4
There are about 90 serotypes (strains) of the bacteria – S. pneumoniae – that cause pneumococcal disease. The spectrum of prevailing capsular types varies with age, time and geographical region, although common serotypes are consistently identified throughout the world.
The significant burden of pneumococcal disease and demonstrated efficacy of the 7-valent pneumococcal conjugate vaccine (PCV7) prompted the World Health Organization (WHO) to recommend the priority inclusion of PCV7 in national childhood immunization programs worldwide.3
Following inclusion of PCV7 into the routine U.S. pediatric immunization schedule, there has been a 98 per cent reduction in vaccine-type IPD among infants and toddlers younger than five years of age compared with a prelicensure baseline.3 In addition, the incidence of disease caused by the seven serotypes in PCV7 declined 55 per cent among adults 50 years of age and older, an un-vaccinated group.
Introduction of PCV7 has also been accompanied by a reduction in resistance to antimicrobials in strains covered by PCV7. After the introduction of PCV7, the United States had an 80 per cent decline in invasive pneumococcal disease caused by penicillin-resistant strains in vaccinated young children. Importantly, rates of penicillin-resistant IPD also decreased in all other age groups.5
Most recently, the pneumococcal serotype 19A, not covered by PCV7, has been increasing in prevalence in many regions of the world and is frequently resistant to antibiotics.6,7
PCV13 is an investigational vaccine that includes the 13 most prevalent serotypes associated with serious pneumococcal disease. Seven of these serotypes (4, 6B, 9V, 14, 18C, 19F and 23F) are included in Prevenar. The six additional serotypes (1, 3, 5, 6A, 7F and 19A) are associated with the greatest burden of remaining invasive disease. The Company initiated global pediatric filings for the candidate vaccine in 2008. The Company expects to complete the U.S. filing for pediatric use of the vaccine in the first quarter of 2009. The 13-valent candidate vaccine is also being studied in global Phase 3 clinical trials in adults, with regulatory filings expected in 2010.
“Since its introduction, Prevenar has had a substantial impact on public health, dramatically reducing the rate of invasive pneumococcal disease where it is routinely used. Our investigational 13-valent pneumococcal conjugate vaccine is designed to broaden protection, with the potential to cover up to 93 per cent of invasive pneumococcal disease in infants and young children worldwide,” says Emilio Emini, Ph.D., Executive Vice President, Vaccine Research and Development, Wyeth Pharmaceuticals.
PCV7 (PREVENAR (Pneumococcal Saccharide Conjugated Vaccine, Adsorbed)) is the first vaccine to help prevent pneumococcal disease (PD) caused by vaccine serotypes, including sepsis, meningitis, pneumonia and acute otitis media (middle ear infections).
PREVENAR is now commercially available in more than 90 countries worldwide and is part of the routine childhood immunization schedule in 35 of those countries.
PREVENAR was discovered and developed by Wyeth Vaccines, a division of Wyeth (NYSE: WYE).
For more information visit www.wyeth.com
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NOTES TO EDITORS
Wyeth is one of the world’s largest research-driven pharmaceutical and health care products companies. It is a leader in the discovery, development, manufacturing and marketing of pharmaceuticals, vaccines, biotechnology products, nutritionals and non-prescription medicines that improve the quality of life for people worldwide. The Company’s major divisions include Wyeth Pharmaceuticals, Wyeth Consumer Healthcare and Fort Dodge Animal Health.
1.L Xue, KH Yao, ZJ Liu, SJ Yu, YH Yang. Antibiotic Resistance of Serotype 19A Streptococcus pneumoniae Isolated from Children in Beijing Children’s Hospital, 2000-2007. Abstract Presentation at 7th International Symposium on Antimicrobial Agents and Resistance (ISAAR).
2.Zunjie Liu, Kaihu Yao, Sangjie Yu,Lin Yuan,Yonghong Yang. Epidemiology of serogroup 6 Streptococcus pneumoniae isolates from children in Beijing, China. Abstract Presentation at 7th International Symposium on Antimicrobial Agents and Resistance (ISAAR).
3.WHO (2007). “Pneumococcal conjugate vaccine for childhood immunization – WHO position paper”. Wkly Epidemiol Record; 82(12): 93-104.
4.Rudan I, Boschi-Pinto C, Biloglav Z, Mulholland K & Campbelle H. Epidemiology and etiology of childhood pneumonia. Bulletin of the World Health Organization 2008; 86:408-416.
5.Kyaw MH, Lynfield LR, Schaffner W, et al (2006). Effect of introduction of the pneumococcal conjugate vaccine on drug-resistant Streptococcus pneumoniae. N Engl J Med;354:1455-1463.
6.Hicks LA, Harrison LH, Flannery B, et al. Incidence of pneumococcal disease due to non-pneumococcal conjugate vaccine (PREVENAR) serotypes in the United States during the era of widespread PREVENAR vaccination, 1998-2004. J Infect Dis. 2007;196:1346-1354
7.Choi EH, Kim SH, Eun BW, et al. Streptococcus pneumoniae serotype 19A in children, South Korea. Emerg Infect Dis 2008;14:275-281