ATLANTA – The Centers for Disease Control and Prevention’s vaccine advisory panel is holding off on a recommendation for use of the 13-valent conjugate pneumococcal vaccine in adults, despite its December 2011 licensure for those aged 50 years and older.
At its February 2012 meeting, the Advisory Committee on Immunization Practices reviewed the evidence for the use of PCV13 in adults aged 65 years and older and in immunocompromised adults. The full committee agreed with a prior recommendation from its Pneumococcal Vaccines Work Group that there is insufficient evidence at this time to determine the value of immunizing adults with PCV13. Currently missing are data on efficacy, expected to be available in 2013 from an ongoing Dutch trial, and information about the indirect impact of the current routine use of PCV13 in children on herd immunity in adults, work group chair Dr. Nancy M. Bennett said.
In contrast to ACIP’s evidence-based approach, the Food and Drug Administration based its adult approval of PCV13 (Pfizer’s Prevnar 13) on noninferiority, compared with the 23-valent pneumococcal polysaccharide (PPSV23) vaccine, and on safety, explained Dr. Bennett, professor of medicine and community and preventive medicine at the University of Rochester (N.Y.).
PCV13 "is very promising in the prevention of pneumococcal disease in all age groups. ... The ACIP was asked to consider all of the evidence related to the use of the vaccine in adults. At this time, we are not prepared to make a recommendation. We are in the process of reevaluating all the evidence that’s available. The important thing to realize is that there’s a difference between licensure by the FDA and a recommendation from the ACIP," she said in an interview.
Dr. Nancy Bennett
The current plan – subject to revision – is for ACIP to vote at its June 2012 meeting on use of PCV13 in immunocompromised adults (for whom the data in favor of PCV13 use are stronger) and to review data from the CDC’s Active Bacterial Core surveillance to see whether routine use of PCV13 in children indirectly reduces the rates of disease in adults, as occurred with the previous 7-valent pneumococcal conjugate vaccine (J. Infect. Dis. 2010;201:32-41)
In 2013, ACIP is expected to review data from the Community Acquired Pneumonia Immunization Trial in Adults (CAPITA), a randomized, placebo-controlled trial involving 85,000 community-dwelling, pneumococcal vaccine–naive adults aged 65 years and older being conducted in the Netherlands. The study’s primary objective is to determine the efficacy of PCV13 against vaccine-serotype community-acquired pneumonia (CAP). Secondary objectives are to evaluate efficacy against nonbacteremic vaccine-type CAP and vaccine-type invasive pneumococcal disease, all pneumococcal CAP, and death (Neth. J. Med. 2008;66:378-83).
Depending on when those data become available, a vote on the use of PCV13 in adults aged 65 and older (the age group currently targeted for PPSV23) could take place in February or June 2013, Dr. Bennett said.
Of course, PCV13 is licensed for adults aged 50 years and older, so physicians are able to use the vaccine in those individuals if they so choose. In an interview, Dr. William Schaffner, a member of the pneumococcal work group, said that he has received numerous questions from physicians about use of PCV13 in adults. For example, they want to know if patients who are already immunized with PPSV23 might benefit from receiving a dose of PCV13 since it provides better immunogenicity, better boosting, and unlike PPSV23, is likely to eliminate pneumococcal carriage.
Moreover, physicians have asked him whether new patients who are eligible for pneumococcal vaccine should be given PCV13, PPSV23, or perhaps both (to obtain both the presumed advantages of PCV13 along with protection against the extra 10 serotypes from PPSV23). And if they should be given both, can the two vaccines be administered simultaneously or must they be given in sequence? And if in sequence, which vaccine should be given first and what should be the interval in between?
Dr. William Schaffner
Those questions have not been answered as yet, but, Dr. Schaffner said in an interview, "If I have a 67-year-old patient who is overweight, has diabetes, and has smoked – not an unusual combination – I want to do everything I can to make this specific patient who is sitting in front of me have the maximum protection. [Then] there may be a clinical reason to use this vaccine. Sometimes the public health decision may be different from an individualized clinical decision."
Dr. Schaffner, chair of the department of preventive medicine at Vanderbilt University in Nashville, Tenn., said data suggest that such a patient would likely receive maximal protection with a dose of PCV13 first, followed by a PPSV23 dose 6-8 weeks later. He acknowledged that this might be impractical for a variety of reasons. For one thing, although Medicare is expected to cover PCV13 under Part B, it is not clear whether it would cover both vaccines given in sequence. Thus, he said, "at the moment I would say to physicians, ‘Keep doing what you’re doing, and stay tuned.’ "