BACKGROUND: When the Advisory Committee on Immunization Practices added the sequential schedule to the poliovirus vaccine (PVV) recommendations in 1997, primary care physicians expressed concern about its implementation. This study examines the practices and factors influencing the administration of sequential, oral, or inactivated PVV schedules by family physicians and pediatricians.
METHODS: A random sample of Ohio family physicians and pediatricians was surveyed between January and April 1998. Primary outcome measures included physicians’ awareness of the 1997 recommendations, their recommendations to parents and caregivers, administration of current PVV options, and the factors influencing their practices.
RESULTS: All physicians who immunize children (n = 263) reported awareness of the 1997 PVV recommendations. Family physicians were more likely to recommend and administer oral polio vaccine than pediatricians (50% and 63% vs 17% and 28%; P <.001). Pediatricians were more likely to recommend and administer the sequential schedule than family physicians (66% and 67% vs 31% and 28%; P <.001). Choice of sequential schedule was related to the risk of vaccine-associated paralytic poliomyelitis and liability (P · .05). Choice of an all oral polio vaccine schedule was related to cost of inactivated PVV and increased number of injections (P · .05). One hundred eighty-two physicians (69%) indicated that they personally discuss PVV options with parents or caregivers; only 41% have them read the required vaccine information sheets.
CONCLUSIONS: Differences exist between family physicians’ and pediatricians’ implementation of the 1997 PVV recommendations. Physician choice of PVV schedule is influenced by the risk of vaccine-associated paralytic poliomyelitis, increased number of injections, liability concerns, and vaccine cost. Physicians need to inform parents of vaccine benefits and risks to comply with federal regulations.
In January 1997, the Advisory Committee on Immunization Practices (ACIP) revised the poliovirus vaccination schedule to include 3 options. The ACIP, an advisory group of the Centers for Disease Control and Prevention, recommended a sequential schedule of 2 doses of inactivated poliovirus vaccine (IPV) followed by 2 doses of oral poliovirus vaccine (OPV), but also considered the all OPV or IPV schedules acceptable.1 The recommendation was made on the basis of the following: (1) there had been no indigenously acquired case of wild-type poliovirus in the United States since 1979 or in the Americas since 1991; (2) the Western Hemisphere was certified to be free of indigenous wild poliovirus in 1994; (3) 8 to 9 cases of vaccine-associated paralytic poliomyelitis (VAPP) had occurred in the United States each year since 1980; and (4) the sequential schedule was expected to significantly decrease the risk of VAPP.1 An all OPV schedule was still acceptable and even preferred in certain circumstances, such as the need for accelerated protection.1-3 Both the American Academy of Family Physicians and the American Academy of Pediatrics recommended that parents and caregivers be offered a choice of one of the 3 schedules after the known risks and benefits had been explained.2,4
Concerns expressed about the use of IPV include the additional injections, the cost of administration, the possibility of additional visits, decreased acceptability by parents, and subsequent decreased compliance.5-8 Additional concerns were the limited availability of combination vaccine products, the potential need to continue the intestinal immunity induced by OPV,3,8 and the effectiveness of the sequential schedule in preventing VAPP.6,7
The additional costs of implementing the sequential schedule were estimated to total $14.7 million or $3.1 million for each case of VAPP prevented.9 For the practitioner, IPV requires more staff time and costs more to administer than OPV, even if the cost of the vaccine is similar. The costs associated with immunizations have been cited as a major barrier to delivery and a primary reason for referral of children to public health departments.10,11
Other factors may contribute to the hesitation to adopt the immunization recommendations by primary care providers. A 9-state survey found that family physicians were slower than pediatricians to adopt hepatitis B vaccine recommendations because of less demand for the vaccine by parents and perceived parental resistance to the vaccine or multiple injections.12 A later 6-state study described the advantages and disadvantages of the all OPV schedule versus the sequential schedule to focus groups of low-income parents. Some parents expressed doubts and concerns about IPV, but a majority preferred the new schedule because of the risk of contracting VAPP with OPV only.13
Provider choice might also be an important factor in the actual administration of poliovirus vaccine (PVV). Focus groups of nurses in county health clinics in Georgia believed that provider recommendations regarding the polio schedules greatly influenced parental choice of which PVV schedule they wanted for their child.14 Six Georgia public health clinics informed parents of the 3 polio vaccination options, recommending the IPV-OPV schedule. Eighty-eight percent of infants received their first dose of PVV as IPV and 12% as OPV. Seventy-seven percent of infants receiving IPV returned for their second dose compared with 65% of those infants receiving OPV.15 Sixty-four percent of parents in 2 public health clinics indicated that the risk of VAPP was their greatest concern, 10% were concerned about the extra injection, and 12% were concerned about both.16