How Do Physicians Immunize Their Own Children? Differences Among Pediatricians and Nonpediatricians
Klara M. Posfay-Barbe, MD, MS*, Ulrich Heininger, MD, Christoph Aebi, MD, Daniel Desgrandchamps, MD||, Bernard Vaudaux, MD and Claire-Anne Siegrist, MD, PD
PEDIATRICS Vol. 116 No. 5 November 2005, pp. e623-e633
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CONCLUSIONS
Little is known about the immunization practices of physicians regarding their own children.22 The results of this study suggest that although 93% of the surveyed physicians agree with current official vaccination recommendations and would apply them to their own children, this opinion is not shared by a significant proportion of nonpediatricians who were twice as likely not to have followed (and, hypothetically, not to follow in 2004) the official recommendations for their own children.
DTP-polio–immunization rates were remarkably high in children of both groups of physicians. In contrast, Hib coverage was significantly lower. This reflected in part its more recent availability (1990), because 97.3% of the physicians with children <5 years old had protected their children against Hib. However, the observation that 5% of nonpediatricians would not use the Hib vaccine if they had a child born in 2004 is unexpected, given the severity of the disease, the high efficacy and safety of Hib vaccines, and the availability of DTaP-IPV/Hib pentavalent combination vaccines, which prevents an additional shot. This observation is supported by the fact that only 94.1% of nonpediatricians (compared with 98.3% of pediatricians) would use a pentavalent vaccine for their own children in 2004. Reasons evoked by physicians declining the use of Hib vaccines for their own children included lack of awareness ("no invasive Hib disease seen in 25 years of private practice") but also reflected a subjective relative-risk analysis led by the desire to reduce vaccines to a minimum ("risk currently minimal in my area") (Table 4). It is fortunate that a 4-dose Hib-immunization schedule induces efficient herd immunity in Switzerland and elsewhere.
Hepatitis B immunization was introduced into the Swiss immunization schedule in 1998 and is currently officially recommended at 11 to 15 years of age, and hepatitis B immunization containing hexavalent infant vaccines was introduced as an alternative in 2001. Only a minority (30.4%) of nonpediatricians would use such a hexavalent combination vaccine for their children in 2004. However, 94.8% of physicians would immunize their own children against hepatitis B in 2004, which is significantly higher than the median national immunization rate (52%) recorded in 2003.24
In contrast, observed and projected rates of MMR immunization by nonpediatricians are of concern. Although acceptance rates are much higher than in the general population (84%),25,26 almost 5% of physicians in this survey did not use the MMR vaccine and would not give it to their own children in 2004. The main reasons evoked by this minority of physicians include the wish to avoid trivalent combined vaccines because of safety concerns, the preference for infection-driven rather than vaccine-induced immunity, and the conviction that homeopathic treatment allows a benign outcome of measles, mumps, and rubella. These are frequent beliefs in the general population and that they are supported by physicians who adhere to alternative medicine concepts is not unexpected.27,28 The impact of misconceptions regarding MMR vaccines can be appreciated by the recent autism–MMR-vaccine controversy, which led to a decrease in MMR-immunization levels in the United Kingdom.18,29–31 It therefore represents a significant threat to the World Health Organization’s program to eliminate measles from the European region and may predict the persistent circulation of the measles virus and consecutive outbreaks.15–17,32 Indeed, herd immunity is thought to succeed in the control of measles only when immunization levels are >93% to 95%.33
The belief that immunization may be initiated "too early" is also a frequent parental concern fueled by theoretical issues such as immune overload.3,34,35 Again, almost 10% of nonpediatricians indicated that they would initiate DTaP immunization beyond the age of 4 to 6 months and 15% would not give the first dose of measles or MMR vaccine before 2 years of age, thus contributing to the maintenance of a reservoir of susceptible nonimmune young children.
A contrasting observation of this survey was the relatively frequent use of additional vaccines that physicians chose for their own children despite the lack of reimbursement. The use of hepatitis A vaccine was similar in both groups of parent physicians, probably reflecting similar travel attitudes. Pediatricians were much more likely to offer additional vaccines to their children than nonpediatricians. This was most marked for the pneumococcal conjugate vaccine, currently only recommended for high-risk groups in Switzerland, and the group C meningococcal conjugate vaccine, which possibly reflects the greater experience of pediatricians with serious outcomes of the diseases caused by these organisms and/or their greater access to information and training opportunities on these recently available vaccines.36–38 The observation that nonpediatricians were 3 times more likely to select the BCG vaccine for a newborn child in 2004 despite its withdrawal from the Swiss routine-immunization schedule in 1987 indirectly suggests the importance of continuous education in vaccine-related issues. In contrast, immunization against TBE was selected twice as often by nonpediatricians, which might reflect the fact that immunization against TBE is recommended in Switzerland for adults and children >6 years of age living in endemic areas, and general practitioners or internists are more used to its administration than pediatricians.
Our results must be interpreted in the context of several methodologic limitations. The Web-based survey was pilot tested for usability but not validated for reliability or external validity. The first part of this survey might have been influenced by a recollection bias, because physicians were asked to remember which vaccines were given to their own children, sometimes several decades before. However, the second part explored how physicians, hypothetically, would immunize their children if born in 2004 (ie, at the time of the survey). Here, a response-effect bias is possible but unlikely because there are no "right" answers. Self-reported evaluations by physicians have already been used successfully in other areas.39 Recruiting subscribers to InfoVac, a nonprofit Web-based expert group on immunization issues, and the 50% response rate introduces several obvious biases. Although the survey reached >95% of the pediatricians, the proportion of nonpediatricians was much more limited. It is most likely that subscribers to the InfoVac services, and among them survey participants, are more directly interested in immunization issues, such that our results cannot be generalized to all physicians. This is especially true for nonpediatricians who have to actively register with InfoVac. Thus, the differences observed between pediatricians and nonpediatricians answering this survey are of primary importance, because both groups are particularly interested in vaccination issues. The observation that significantly lower immunization rates were indicated by nonpediatrician parents is of concern: vaccine use could be even lower for nonpediatrician physicians who were not reached by this survey, increasing the difference between pediatricians and nonpediatricians even further.
In conclusion, 95% of pediatricians practicing in Switzerland immunize, or would immunize, their children according to recommended schedules and vaccines. They give at least as many vaccines to their own child as to their patients (and frequently many more), immunize as early as recommended, and also make a comprehensive use of the most recent combination vaccines. In contrast, a relatively large proportion of nonpediatricians do not follow, nor plan to follow, current immunization recommendations for their own children. Despite their scientific training and education, they express the same concerns as those that prevail in the public. Although this survey cannot establish the effectiveness of Swiss physicians as role models for immunization, it is known that convinced physicians are more apt to provide their patients with vaccines that they believe to be beneficial.40–43 Thus, unless additional vaccine education and information efforts targeted toward these physicians eventually prove successful, the control of communicable diseases such as measles may prove impossible in Switzerland and other countries.