659. Mumps Outbreak in a High School: Uptake and Parental Perceptions of Third Dose MMR Recommendations, Dallas County, Texas, 2017

Background

In February 2017, a mumps outbreak was identified in a large Dallas high school among students who had previously completed the two-dose MMR vaccination series. Early notification of recommendations for third dose MMR and free vaccination clinics provided an opportunity to assess vaccine uptake, efficacy, and parental perceptions of third dose MMR recommendations.

Methods

Mumps illnesses were classified as probable or confirmed cases using 2012 CSTE case definitions. Information about vaccination status, exposure history, and illness characteristics was collected from case interviews and medical records. A third MMR vaccine was recommended to all noncase students and offered without charge at school-based vaccination clinics. Supplemental questionnaires assessing parental knowledge and attitudes regarding this third MMR recommendation were administered to guardians of a randomly selected sample of 20 students who received third dose MMR and 50 students who did not receive the vaccine. Fishers exact tests and chi-square were used to compare responses. Data analysis was performed using SAS 9.4.

Results

From February to May 2017, 28 PCR-confirmed and 12 probable mumps cases were identified in students attending one high school campus (24.3 cases per 1,000 students). Of the 1,646 enrolled students, 99.8% had documentation of at least two doses of MMR prior to the outbreak, including all mumps cases. Three undervaccinated students who declined to receive one dose of MMR were excluded from school during the outbreak. Following public health recommendations for a voluntary third MMR dose, 291 students (17.6%) elected to receive a third MMR. No mumps cases occurred in students who received a third vaccine dose. Parental perception of protective benefit of an additional third dose of MMR was significantly associated with decisions to receive third dose MMR (OR: 4.9; 95% CI = 1.6–15.3).

Conclusion

Responsiveness to health department recommendations for third MMR vaccination in this outbreak setting was limited, even with broad educational communications and free school-based vaccine clinics. The challenges in achieving robust voluntary uptake of a third MMR dose may not improve substantially despite recent ACIP recommendations, in the absence of school mandates requiring third dose of MMR during outbreaks.

Disclosures

All authors: No reported disclosures.

679. Mass-Scale Post-Hurricane Sheltering of Evacuees From Hurricane Harvey: Infectious Disease Surveillance and Prevention: Dallas County, Texas, 2017

Background

The record rainfall following Hurricane Harvey’s landfall along the Texas coast on August 25, 2017 caused prolonged, widespread flooding, which devastated Houston and areas along the southern Gulf Coast. With shelters in Houston at capacity, residents from adjacent affected regions were evacuated elsewhere, and Dallas received over 3,800 evacuees at a single convention center shelter. Approaches to infectious disease surveillance and prevention in this mega-shelter setting were assessed and refined during the response.

Methods

Teams of epidemiologists and medical students reviewed all clinical records daily from the on-site, 24/7 walk-in medical clinic, which was staffed by local volunteer physicians. Demographic data, chief complaints, and diagnosis for each patient visit were reviewed, and daily aggregate summaries of visits for potential communicable disease symptoms were compiled. An additional infection control team consisting of health department staff and volunteer hospital infection preventionists implemented aggressive infection prevention measures in the shelter and clinic.

Results

Of the evacuees registered at this mass-scale shelter, 92% were from counties outside of Houston and 36% were 18 years of age or younger. During the shelter’s 23 days of operation, the shelter medical clinic received a cumulative volume of 2,654 clinic visits from 1,560 evacuees. The most common reasons for clinic visits included: need for medication refills (27.2%); respiratory symptoms (18.8%); and skin-related complaints (8.6%). Isolated cases of scabies, lice, norovirus, and influenza were confirmed, with no outbreak transmission of communicable diseases reported in the shelter.

Conclusion

The need for acute-care medical services and resources at a central shelter location was highlighted by the high proportion (40%) of evacuees seeking care at least once at the shelter medical clinic. The 24/7 accessibility of this on-site medical clinic to evacuees additionally provided a reliable mechanism for daily syndromic surveillance for potential outbreaks of infectious disease in a large shelter. Given the challenges of mass-sheltering and provision of clinical care in non-residential structures, dedicated staffing with infection control expertise was critical in this shelter setting.

Disclosures

All authors: No reported disclosures.

Cognitive decision strategies adopted by consumers in reminder difference tests: Influence of the authenticity test

Discrimination tests are used in food companies to quantify small differences between products. Within the diversity of methods available, some are quicker to conduct, whereas others are more sensitive or statistically powerful. One class of methods includes the reminder tasks in which the reference product is given before tasting the actual test stimuli. During the task, such a 'reminder' can be compared directly to each test stimulus, or alternatively, only serve to prime the memory of the judge without being taken into account in decision-making. Previous research with trained judges provided evidence for the latter process while research with untrained consumers has provided some evidence for the former process. Two studies were conducted with untrained consumers using the A Not-AR and 2-AFCR reminder tasks. Objectives were to determine the decision strategies used in, and the relative sensitivity of the tasks. In addition, the use of an "authenticity test" was explored to see if this has a positive effect on test performance. In the first study, mayonnaise and ice tea with small stimulus differences (d'<1) were used in A Not-AR and 2-AFCR. Results were compared to those from A Not-A and 2-AFC tasks, with and without an authenticity test. It was difficult to draw clear conclusions on the decision strategy used, though the use of an authenticity test increased the sensitivity for these small differences, as it improved the performance of 6 out of 8 tests. In the second study, ice teas with larger stimulus differences (at two levels) were tested using the A Not-AR and 2-AFCR tasks, in comparison to the same-different task. The results showed that consumers use the less optimal strategies and that the authenticity test decreases performance, which is contradictory to the results of the first study. It seems that for very small stimulus differences the authenticity test can improve performance, but with larger differences the authenticity test decreases performance; it seems to confuse the judges.

Burden of disease from inadequate water, sanitation and hygiene in low- and middle-income settings: a retrospective analysis of data from 145 countries

OBJECTIVE

To estimate the burden of diarrhoeal diseases from exposure to inadequate water, sanitation and hand hygiene in low- and middle-income settings and provide an overview of the impact on other diseases.

METHODS

For estimating the impact of water, sanitation and hygiene on diarrhoea, we selected exposure levels with both sufficient global exposure data and a matching exposure-risk relationship. Global exposure data were estimated for the year 2012, and risk estimates were taken from the most recent systematic analyses. We estimated attributable deaths and disability-adjusted life years (DALYs) by country, age and sex for inadequate water, sanitation and hand hygiene separately, and as a cluster of risk factors. Uncertainty estimates were computed on the basis of uncertainty surrounding exposure estimates and relative risks.

RESULTS

In 2012, 502,000 diarrhoea deaths were estimated to be caused by inadequate drinking water and 280,000 deaths by inadequate sanitation. The most likely estimate of disease burden from inadequate hand hygiene amounts to 297,000 deaths. In total, 842,000 diarrhoea deaths are estimated to be caused by this cluster of risk factors, which amounts to 1.5% of the total disease burden and 58% of diarrhoeal diseases. In children under 5 years old, 361,000 deaths could be prevented, representing 5.5% of deaths in that age group.

CONCLUSIONS

This estimate confirms the importance of improving water and sanitation in low- and middle-income settings for the prevention of diarrhoeal disease burden. It also underscores the need for better data on exposure and risk reductions that can be achieved with provision of reliable piped water, community sewage with treatment and hand hygiene.