A look into the reasoning behind the vaccine recommendations set by the CDC's Advisory Committee on Immunization Practice.
William Schaffner, MD
This June, the Centers for Disease Control and Prevention (CDC) Advisory Committee on Immunization Practices (ACIP) agreed in a vote to revise the current guidelines for adult pneumococcal vaccination.
The new guideline recommends physicians administer an initial dose of pneumococcal 13-valent conjugate vaccine (PCV13; Prevnar 13) to unvaccinated, immunocompetent adults aged 65 years or older, before then administering a dose of pneumococcal vaccine polyvalent (Pneumovax 23) at a later period.
The process, at the surface, appears complicated. When given context, there’s an understanding of the 2 vaccine’s method and capability with pneumococcal bacteria prevention. It’s also still complicated, though.
In a recent interview with MD Magazine®, William Schaffner, MD, a professor of Preventive Medicine, Department of Health Policy at Vanderbilt University Medical Center, broke down the new guideline recommendation, the pediatric benefit of PCV13 which drove the decision, and means by which it can improve clinical decisions surrounding vaccination.
MD Mag: Could you highlight the most recent change to ACIP guidelines for adult pneumococcal vaccination?
Schaffner: Tighten your seatbelts a little bit, because the recommendations for the use of pneumococcal vaccines in adults are a bit complicated. There are 2 vaccines available; the first is PCV13, a conjugate vaccine which covers 13 serotypes. And then there is the older pneumococcal polysaccharide vaccine which covers 23 types.
And sometimes, one of them is recommended. Sometimes, both are recommended for people. The first thing is that PCV13 is recommended universally for children in the US. This is widely accepted by pediatricians and family doctors, and parents for their children, and it has had a spectacular effect in fruitfully eliminating invasive, serious pneumococcal disease akin to those 13 serotypes in children.
The other thing that vaccine does is it virtually eliminates the carriage of those 13 serotypes, asymptomatically in children. As a consequence, an unanticipated but very dramatic indirect effect occurred. It turns out children carry pneumococci back in their nasal pharynx, one of the great distributors of pneumococci in the population. So when they hug their mother, dad, aunt, grandpa, they use to disseminate those serotypes to adults. Then, adults would get sick.
But because we use PCV13 universally in kids, the carriage of those serotypes has been either eliminated or profoundly reduced. Children are no longer transmitting those serotypes to adults, and so adults have had a consequent profound diminution in invasive disease due to those serotypes even though they have not been vaccinated.
MD Mag: What about vaccination for adults?
Schaffner: Once you get to the 19th birthday, in the immunization world, you’re an adult. So what are the recommendations for pneumococcal vaccinations in adults? First, it’s risk-based. If you have certain underlying medical conditions—such as chronic heart disease, lung disease, diabetes, alcoholism, chronic liver disease, or if you are a cigarette smoker—it is recommended you get polysaccharide vaccine.
Then there are an additional set of conditions, as well as immunocompromised patients, who should get both PCV13 and polysaccharide vaccine, separated by an interval. PCV13 should be administered first, in order to get an optimal immune response.
MD Mag: What does this mean for older patients?
Schaffner: If you’re immunocompromised, you’re still eligible for these vaccines. But let’s talk about 65 year-olds that are still healthy, those who have not received a pneumococcal vaccine before. Until recently, it was recommended they receive both conjugate vaccine and polysaccharide vaccine.
But because the indirect effect of vaccinating kids with PCV13 has been so profound, the CDC changed its recommendation and said it’s a shared clinical decision, if you’re 65 and healthy, whether you need PCV13. Some of you may choose to get it, some of you may not. But regardless, all of you should get polysaccharide vaccine.
This is a very complicated set of recommendations.
MD Mag: Are there any resolutions to guidelines or treatment policies that would simplify this process?
Schaffner: I’m in a difficult position, because I represent the National Foundation for Infectious Diseases (NFID), and it promotes the ACIP recommendations. But, it is within the spirit of the ACIP recommendation that if the doctor thinks providing everyone 65 years and older with both vaccines is the way to go—you might think of it as the ‘belt’ or ‘suspenders’ approach—you’re within the ACIP recommendations, because it’s shared clinical decision making.
And the anticipation is that Medicare will continue to pay for both vaccines.