This survey was designed and conducted in collaboration with CDC as part of the Vaccine Policy Collaborative Initiative, which designs and executes surveys to assess physician knowledge, attitudes, and practices about vaccination. We surveyed pediatricians from a sentinel network recruited to be representative of the American Academy of Pediatrics’ membership.^{22, 23} Census location was determined based on self-reported zip code matched with most recent census urban/rural classification.

The survey (Appendix 1) was developed in collaboration with CDC, pretested by a national advisory panel of pediatricians (n=6), and piloted among a national sample of physicians (n=26). Based on pediatrician feedback, survey questions were revised for clarity and response choices revised to better reflect experiences of practicing physicians. Pediatricians were asked whether they had ever had a patient with confirmed mumps in their practice. Mumps knowledge was evaluated using a series of true/false questions that included a ‘don’t know’ response option. To assess how often physicians would test patients for mumps in a variety of patient scenarios and how frequently they would order different diagnostic tests to determine the cause of parotitis, four-point Likert scales were used (‘Never’ to ‘Often/Always’). Physicians were asked whether they would test a patient in the office or send them elsewhere for a buccal specimen for mumps RT-PCR, whether they would need guidance for several aspects of testing, and how they would interpret different mumps test results. To evaluate how often pediatricians would report a suspected or confirmed case of mumps to public health authorities, four-point Likert scales were used (‘Never’ to ‘Often/Always’). To assess physician response to a mumps outbreak, a four-point Likert scale to ask how likely they would be to give a third dose of MMR to different patients (‘Very unlikely’ to ‘Very likely’). Physician and practice characteristics assessed included physician gender and age; practice location, size, and type; and practice level of decision-making about vaccines.

Based on physician preference, the survey was sent via Internet (Qualtrics^XM) or mail. We sent the Internet group an initial email with up to eight e-mail reminders, and sent the mail group an initial mailing with up to three reminders.²³ Non-respondents from the Internet group were also sent up to three mail surveys. The mail protocol was modeled after Dillman’s Tailored design method.²⁴ Participants did not receive incentives or payment for participation. Respondents were able to skip items in mail and Internet surveys.

Internet and mail responses were combined for analyses because prior work has shown physician attitudes are similar when obtained by either method.^25–27 We compared respondents to non-respondents using t-tests, Wilcoxon tests, and chi-squared tests, as appropriate. To assess knowledge and testing practices, we calculated the proportion of respondents choosing correct responses for true/false items and reporting different testing practices. Chi-squared and t-tests were used to compare physician and practice characteristics between respondents who would rarely or never and who would sometimes or often/always test for mumps in a 17-year-old adolescent with parotitis who is fully vaccinated in a non-outbreak setting, a scenario in which mumps testing should be considered. Because logistic regression yields odds ratios that overestimate the effect when the prevalence of an outcome is large (>10%)²⁸, multivariable Poisson regression with robust error variance was used to generate risk ratios.²⁹ Exposure variables for bivariable and multivariable comparisons included available demographic items and whether a respondent had ever had a patient with confirmed mumps in their practice. To assess reporting and outbreak response knowledge and practices, we calculated the proportion of respondents reporting different responses to items about reporting mumps cases and offering mumps vaccination in outbreak scenarios. Analyses were performed using SAS, version 9.4 (SAS Institute, Cary, North Carolina).

More than 60% of pediatricians responded correctly to true/false statements about use of a third dose of MMR vaccine for at-risk groups during a mumps outbreak, role of serum IgG in diagnosing mumps, and timing of serum IgM testing to diagnose mumps (Figure 1). Over half of physicians either responded incorrectly or that they didn’t know regarding statements that previously vaccinated patients who have acute mumps may not have detectable mumps IgM (true), the majority of people in the US who get mumps have been vaccinated (true), and MMR vaccination is effective post-exposure prophylaxis for mumps (false).

When presented with clinical scenarios, physicians reported they would more frequently test for mumps in unvaccinated patients and in outbreak scenarios (Figure 2 online). Over two-thirds of pediatricians reported they would often/always test for mumps in a patient with parotitis plus a mumps complication (meningitis or orchitis) in a non-outbreak scenario. Less than one-third of pediatricians reported they would often/always test for mumps in a patient with a complication of mumps without parotitis in a non-outbreak scenario. In a non-outbreak scenario, 53% of respondents would never or rarely test for mumps in a fully-vaccinated 7-year-old with parotitis, and 41% would never or rarely test a fully-vaccinated 17-year-old with parotitis.

To diagnose the cause of parotitis in a patient of any age, 46% of pediatricians would often/always order serum mumps IgM, 32% would often/always order serum mumps IgG, and 24% would often/always order a buccal specimen for mumps RT-PCR (Figure 3 online). Fewer respondents would test for other causes of parotitis (EBV, HIV, influenza, and other respiratory viruses). Only 2% of respondents would often/always send a urine specimen for mumps RT-PCR to diagnose the cause of parotitis.

Of 46% of pediatricians who would test a patient for mumps in their clinic, rather than sending a patient to a lab or specialist, a majority reported they would need additional guidance: 71% would need guidance on specimen collection, 69% where to send the specimen, 61% how to order the test, and 53% whether to contact the local health department.

When presented with four different scenarios for mumps diagnostic test results, more than 20% of physicians reported they did not know how to interpret results for each scenario (Figure 4). Fifty-three percent of pediatricians reported a positive mumps IgG and negative mumps IgM would lead them to rule out mumps, but this combination of results can often be seen in vaccinated patients with mumps infection. Thirty-six percent of pediatricians reported a negative mumps RT-PCR alone would lead them to rule out mumps, though RT-PCR results can be negative with improper specimen collection technique or timing.

Bivariable analysis comparing responses to the question ‘How often would you test for mumps for a 17-year-old adolescent with parotitis who is fully vaccinated in a non-outbreak setting’ by physician and clinic characteristics found mean provider age and region of the country were associated with reported testing practices (Table 2 online). Multivariable analysis found older physicians [RR 1.08 (1.02–1.33) per 5 year increase in age], rural physicians [RR 1.42 (1.12–1.81)], physicians from the Midwest [RR 1.42 (1.07–1.89)] or Northeast [RR 1.50 (1.15–1.96)], and physicians who had ever had a patient with laboratory-confirmed mumps in their practice [RR 1.46 (1.21–1.76)] were more likely to indicate they would sometimes or often/always test for mumps.

Overall, 97% of pediatricians indicated they would often/always report a patient with laboratory-confirmed mumps to public health authorities; however, only 36% indicated they would often/always report a patient with suspected mumps based on history and physical exam.

Pediatrician responses about likelihood of giving a third dose of MMR vaccine in clinical scenarios related to a mumps outbreak at a local university are presented in Figure 5; 97% of respondents indicated they would very likely give a third dose of MMR to a student who had previously received two doses of MMR and had documentation of being part of a specified group recommended by the health department to get a third dose; this response aligns with public health guidance. Twenty-four percent of physicians reported they would be somewhat/very unlikely to give a third dose of MMR to a student who had previously received two doses of MMR and is part of a specified group recommended by the health department to get a third dose and has positive mumps IgG; forgoing a third MMR dose for patients with positive IgG in this scenario does not match public health guidance. Seventy-one percent of respondents indicated they would be somewhat/very likely to give a third dose of MMR to a student who had previously received two doses of MMR and requests vaccination but is NOT part of the specified groups recommended by the health department to get a third dose.