Although removing a dose from the primary series of 13-valent pneumococcal conjugate vaccine (PCV13) would be cost saving, it would likely cause an increase in disease burden absent greater vaccine coverage, researchers estimated.
Compared with a schedule of three primary doses and a booster (3+1), a schedule of two primary doses and a booster (2+1) would reduce medical and nonmedical costs by an estimated $421 million each year, according to Charles Stoecker, PhD, of the CDC's National Center for Immunization and Respiratory Diseases in Atlanta, and colleagues.
But that savings would come at the cost of an increase in disease burden, including estimated increases of 2.5 deaths, 44 invasive pneumococcal disease cases, 1,500 pneumonia hospitalizations, 10,000 outpatient pneumonia cases, 2,300 tympanostomy tube placements, and 261,000 otitis media cases, the researchers reported online in Pediatrics.
The authors noted that "increases in coverage, perhaps funded by savings from the change in schedule, could entirely offset the health losses from the schedule switch."
That may be true, but realizing such increases may be difficult, according to Emmanuel Walter, MD, MPH, and Dennis Clements, MD, PhD, MPH, of Duke University.
"Whereas coverage for four or more doses of PCV for children ages 19 to 35 months increased during the period between 2007 and 2011, the 84.4% coverage reported for 2011 is now comparable with the four-dose coverage level for diphtheria, tetanus, and acellular pertussis vaccine [DTaP]," they wrote in an accompanying editorial. "[DTaP] coverage remained stable during the same time period, suggesting that improving coverage rates for PCV may be a challenge."
The pneumococcal vaccines have been shown to be effective at reducing disease caused by Streptococcus pneumoniae -- including invasive pneumococcal disease, pneumonia, and otitis media -- but they are the most expensive of the routinely recommended pediatric vaccines at about $100 per dose, according to the researchers.
The U.S. immunization schedule calls for three primary doses from ages 2 to 6 months and one booster dose at 12 to 15 months, but at least 21 countries have moved to a 2+1 schedule. Most studies show that the reduced-dose schedule is as effective as the 3+1 schedule, although a few studies have suggested reduced effectiveness against lower respiratory tract infections and otitis media.
Stoecker and colleagues examined the cost-effectiveness of administering PCV13 with a 2+1 schedule -- removing the 6-month dose -- using a model that followed a single, hypothetical birth cohort of about 4.3 million children. The model assumed that the 3+1 and 2+1 schedules would be equally effective through 6 months and roughly the same after administration of the booster dose.
Data on disease burden and vaccine coverage came from surveillance systems, national surveys, and prior studies.
The model showed that removing the final primary dose would save about $500 million each year, or $421 million after taking into account increases in medical and nonmedical costs per birth cohort.
Considering the expected increase in death, removing one of the primary doses would save society about $6 million for each additional life-year lost. Considering nonfatal outcomes, the 2+1 schedule would save about $300,000 for every quality-adjusted life-year (QALY) lost.
That latter figure ranged from $143,000 to $4 million in sensitivity analyses that included various assumptions regarding effects on otitis media.
The study authors acknowledged that the analysis was limited by the lack of randomized trial data comparing the 3+1 and 2+1 schedules and the dependence on the accuracy of assumptions of vaccine effectiveness.
In their editorial, Walter and Clements advised caution before switching to a reduced-dose schedule, noting that "the majority of cost savings for PCV are related to reductions in costs for treating very frequently occurring infections, such as otitis media, rather than less commonly occurring but more serious life-threatening invasive pneumococcal disease."
"Before contemplating a switch to a three-dose series," they wrote, "it is important to remember the most serious diseases that PCV prevents and assure that the dosing schedule ultimately chosen is up to the challenge of preventing these infections."
The study authors reported that they had no conflicts of interest. All are employed by the CDC.