ATLANTA – A large proportion of children apparently are not receiving the 13-valent pneumococcal conjugate vaccine as recommended by the Advisory Committee on Immunization Practices, surveillance data from the Centers for Disease Control and Prevention suggest.
According to the data from an ongoing evaluation of PCV13 vaccine effectiveness, 86 (78%) vaccine-eligible children out of 110 diagnosed with invasive pneumococcal disease secondary to serotypes unique to PCV13 in the year after the vaccine was introduced had not received the dosing recommended by the Advisory Committee on Immunization Practices (ACIP), Dr. Chad M. Cox reported at the International Conference on Emerging Infectious Diseases.
The ACIP recommendations, published March 12, 2010, call for the same dosing schedule used for PCV7 (immunizations at ages 2, 4, and 6 months, with a booster dose at age 12-15 months). ACIP also called for a single supplemental dose of PCV13 in all children aged 14-59 months who previously received an age-appropriate series of PCV7, and for use of PCV13 for the fourth dose in those who had received only three of the four previously recommended doses of PCV7.
PCV13 includes six additional serotypes not included in PCV7, which was introduced in 2000 using the seven most commonly circulating serotypes.
After the introduction of PCV7, a sharp decrease occurred in disease caused by these seven serotypes, but in more recent years an increase was seen in disease caused by serotypes not covered by PC7. Because of the emergence of this "replacement disease," PCV13 was introduced, Dr. Cox explained.
"The [PCV13] vaccine was readily available soon after [the March 2010 ACIP recommendations], and quickly replaced PCV7 in most provider’s offices," said Dr. Cox of the CDC in Atlanta.
Nonetheless, in June 2011 the California Department of Health reported a fatal case of invasive pneumococcal disease in a 2-year-old, which was caused by a serotype in the PCV13 vaccine; 30 additional cases were identified in counties not included in the CDC surveillance area.
This led to a health advisory issued in August 2011 – reminding providers of the ACIP recommendations – and to this study of outcomes in 10 participating surveillance areas representing 3.8 million children under age 5 years.
The hospitalized children in this study included those from the surveillance areas for whom complete vaccination information was available. About two-thirds were aged 2-4 years, Dr. Cox said.
About two-thirds of patients in the study were noncompliant because they had not received a supplemental PCV13 dose after completion of the PCV7 series, and about one-fifth had not received the fourth dose in the series, which should have been a PCV13 dose, he noted.
The majority of the children (93%) had no underlying medical conditions, and 79% were hospitalized. No deaths occurred.
These findings demonstrate that invasive pneumococcal disease resulting from pneumococcal serotyopes unique to PCV13 continued to occur in those who did not receive the recommended dose of PCV13 in the year after it became available, Dr. Cox said.
Prevention of invasive pneumococcal disease requires that a single supplemental dose of PCV13 be given to all children aged 14-59 months who have received an age-appropriate series of PCV7, he said. Efforts have been made, using these and other CDC data, to better educate health care professionals about the ACIP recommendations.
"This is something we continue to watch," he said, noting that the vaccine effectiveness evaluation will continue for 2 more years.
Dr. Cox said that he had no relevant financial disclosures to report.