Dosing schedule of pneumococcal vaccine linked with increased risk of getting multiresistant strain

Public release date: 7-Sep-2010 – EEV: Requested Re-Post from the HRR site.

Infants who received heptavalent pneumococcal conjugate vaccination (PCV-7) at 2, 4, and 11 months were more likely than unvaccinated controls to have nasopharyngeal acquisition of pneumococcal serotype 19A

– the increase in serotype 19A disease was associated in time with the widespread implementation of PCV-7 in routine infant immunization programs

– A rapid increase in the presence of pneumococcal serotype 19A strains that are often multiresistant to antibiotics has been observed over the last decade

– serotype 19A is now the leading causative pneumococcal serotype of invasive and respiratory pneumococcal disease

Question mark in Esbjerg
Question mark in Esbjerg (Photo credit: alexanderdrachmann)

Infants who received heptavalent pneumococcal conjugate vaccination (PCV-7) at 2, 4, and 11 months were more likely than unvaccinated controls to have nasopharyngeal (in the nasal passages and upper part of the throat behind the nose) acquisition of pneumococcal serotype 19A, a leading cause of respiratory pneumococcal disease, according to a study in the September 8 issue of JAMA. Continue reading “Dosing schedule of pneumococcal vaccine linked with increased risk of getting multiresistant strain”

Dosing schedule of pneumococcal vaccine linked with increased risk of getting multiresistant strain

 2010 study posted for filing

Contact: Elisabeth A. M. Sanders, M.D., Ph.D. l.sanders@umcutrecht.nl JAMA and Archives Journals

This release is also available in Chinese on EurekAlert! Chinese.

Infants who received heptavalent pneumococcal conjugate vaccination (PCV-7) at 2, 4, and 11 months were more likely than unvaccinated controls to have nasopharyngeal (in the nasal passages and upper part of the throat behind the nose) acquisition of pneumococcal serotype 19A, a leading cause of respiratory pneumococcal disease, according to a study in the September 8 issue of JAMA.

“A rapid increase in the presence of pneumococcal serotype 19A strains that are often multiresistant to antibiotics has been observed over the last decade. In the United States, serotype 19A is now the leading causative pneumococcal serotype of invasive and respiratory pneumococcal disease and the most frequently observed serotype in nasopharyngeal carriage. In the United States and other countries, the increase in serotype 19A disease was associated in time with the widespread implementation of PCV-7 in routine infant immunization programs,” according to background information in the article. “Because spontaneous fluctuations in time and antibiotic selective pressure may have induced this serotype 19A increase, controlled studies are needed to assess the role of PCV-7.”

Elske J. M. van Gils, M.D., of University Medical Center Utrecht, the Netherlands, and colleagues examined the association between PCV-7 vaccination and nasopharyngeal acquisition of serotype 19A pneumococci in 1,003 healthy newborns, with follow-up to the age of 24 months in the Netherlands, which has low antibiotic resistance rates. The study was conducted before widespread PCV-7 implementation in infants, between July 2005 and February 2008. Nasopharyngeal swabs were obtained at the age of 6 weeks and at 6, 12, 18, and 24 months. Infants were randomly assigned to receive 2 doses of PCV-7 at 2 and 4 months; 2 + 1 doses of PCV-7 at 2, 4, and 11 months; or no dosage (unvaccinated control group).

Nine hundred forty-eight children completed the study. Fifty-four nasopharyngeal serotype 19A carriage isolates from 318 in the 2-dose group, 66 isolates from 327 in the 2 + 1-dose group, and 33 isolates from 303 in the unvaccinated group were collected from 6 weeks through 24 months. “At 24 months and after having completed the vaccine series, the cumulative proportion of participants with acquisition of a new serotype 19A clone in the 2 +1-dose group was 16.2 percent (53 of 327) vs. 9.2 percent (28 of 303) in the unvaccinated control group. The cumulative proportion in the 2-dose group was also higher than in the unvaccinated group but did not reach statistical significance (13.2 percent; 42 of 318 children),” the authors write.

The proportion of children with new 19A acquisition who had used antibiotics in the last 6 months (18.7 percent) did not differ among groups.

“In addition to the contributing role of antibiotic selective pressure as previously described by others, we now have demonstrated, to our knowledge for the first time, the facilitating role of PCV-7 in nasopharyngeal acquisition of serotype 19A. In view of the proven disease potential of serotype 19A for otitis media and invasive pneumococcal disease and the observed association with antibiotic resistance, vaccines of broader coverage including protection against serotype 19A may further aid to pneumococcal disease prevention. However, we need to be aware that other serotypes with similar characteristics and disease potential may be the next in line to proliferate and therefore pneumococcal surveillance remains important after introduction of expanded pneumococcal conjugate vaccines,” the researchers conclude.

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(JAMA. 2010;304[10]:1099-1106. Available pre-embargo to the media at www.jamamedia.org)

Editor’s Note: Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.

Vaccine tied to ‘superbug’ ear infection – Old Prevnar 2007 Historical Only

*Requested Repost From 2007 – Info is Historical

 

A vaccine that has dramatically curbed pneumonia and other serious illnesses in children is also having an unfortunate effect: promoting new superbugs that cause ear infections

On Monday, doctors reported discovering the first such germ that is resistant to all drugs approved to treat childhood ear infections. Nine toddlers in Rochester, N.Y., have had the bug and researchers say it may be turning up elsewhere, too.

Wyeth anticipated this and is testing a second-generation vaccine. But it is at least two years from reaching the market, and the new strains could become a public health problem in the meantime if they spread hard-to-treat infections through day care centers and schools.

It is a strain of strep bacteria not included in the pneumococcal vaccine, Wyeth’s Prevnar, which came on the market in 2000. It is recommended for children under age 2.

Prevnar, however, is losing its punch because strains not covered by the vaccine are filling the biological niche that the vaccine strains used to occupy, and they are causing disease.

One strain in particular, called 19A, is big trouble. A new subtype of it caused ear infections in the nine Rochester children, ages 6 months to 18 months, that were resistant to all pediatric medications, said Dr. Michael Pichichero, a microbiologist at the University of Rochester Medical Center.

The children had been unsuccessfully treated with two or more antibiotics, including high-dose amoxicillin and multiple shots of another drug. Many needed surgery to place ear tubes to drain the infection, and some recovered only after treatment with a newer, powerful antibiotic whose safety in children has not been established.

–Scientists from a drug company and two labs analyzed more than 21,000 bacterial samples from around the nation and found 19A increasing. Among children 2 and under, the portion of samples that were this strain rose to 15 percent in 2005-2006, from 4 percent in the previous three years.

–A British lab tracking respiratory infections in U.S. kids found that the 19A strain accounted for 40 percent of drug-resistant cases.

–University of Iowa researchers found 19A accounted for 35 percent of penicillin-resistant infections in 2004-05, compared with less than 2 percent the year before the new vaccine came out.