Rebecca M. Dahl

Effectiveness of a Third Dose of MMR Vaccine for Mumps Outbreak Control

BACKGROUND The effect of a third dose of the measles–mumps–rubella (MMR) vaccine in stemming a mumps outbreak is unknown. During an outbreak among vaccinated students at the University of Iowa, health officials implemented a widespread MMR vaccine campaign. We evaluated the effectiveness of a third dose for outbreak control and assessed for waning immunity. METHODS Of 20,496 university students who were enrolled during the 2015–2016 academic year, mumps was diagnosed in 259 students. We used Fishers exact test to compare unadjusted attack rates according to dose status and years since receipt of the second MMR vaccine dose. We used multivariable time‐dependent Cox regression models to evaluate vaccine effectiveness, according to dose status (three vs. two doses and two vs. no doses) after adjustment for the number of years since the second dose. RESULTS Before the outbreak, 98.1% of the students had received at least two doses of MMR vaccine. During the outbreak, 4783 received a third dose. The attack rate was lower among the students who had received three doses than among those who had received two doses (6.7 vs. 14.5 cases per 1000 population, P<0.001). Students had more than nine times the risk of mumps if they had received the second MMR dose 13 years or more before the outbreak. At 28 days after vaccination, receipt of the third vaccine dose was associated with a 78.1% lower risk of mumps than receipt of a second dose (adjusted hazard ratio, 0.22; 95% confidence interval, 0.12 to 0.39). The vaccine effectiveness of two doses versus no doses was lower among students with more distant receipt of the second vaccine dose. CONCLUSIONS Students who had received a third dose of MMR vaccine had a lower risk of mumps than did those who had received two doses, after adjustment for the number of years since the second dose. Students who had received a second dose of MMR vaccine 13 years or more before the outbreak had an increased risk of mumps. These findings suggest that the campaign to administer a third dose of MMR vaccine improved mumps outbreak control and that waning immunity probably contributed to propagation of the outbreak. (Funded by the Centers for Disease Control and Prevention.)

First confirmed cases of Middle East respiratory syndrome coronavirus (MERS-CoV) infection in the United States, updated information on the epidemiology of MERS-CoV infection, and guidance for the public, clinicians, and public health authorities - May 2014

Since mid-March 2014, the frequency with which cases of Middle East respiratory syndrome coronavirus (MERS-CoV) infection have been reported has increased, with the majority of recent cases reported from Saudi Arabia and United Arab Emirates (UAE). In addition, the frequency with which travel-associated MERS cases have been reported and the number of countries that have reported them to the World Health Organization (WHO) have also increased. The first case of MERS in the United States, identified in a traveler recently returned from Saudi Arabia, was reported to CDC by the Indiana State Department of Health on May 1, 2014, and confirmed by CDC on May 2. A second imported case of MERS in the United States, identified in a traveler from Saudi Arabia having no connection with the first case, was reported to CDC by the Florida Department of Health on May 11, 2014. The purpose of this report is to alert clinicians, health officials, and others to increase awareness of the need to consider MERS-CoV infection in persons who have recently traveled from countries in or near the Arabian Peninsula. This report summarizes recent epidemiologic information, provides preliminary descriptions of the cases reported from Indiana and Florida, and updates CDC guidance about patient evaluation, home care and isolation, specimen collection, and travel as of May 13, 2014.

Prevalence of Immunosuppression Among US Adults, 2013

Prevalence of Immunosuppression Among US Adults, 2013 The number of immunosuppressed adults in the United States is unknown but thought to be increasing because of both greater life expectancy among immunosuppressed adults due to improvements in medical management, as well as new indications for immunosuppressive treatments.1-4 Immunosuppression increases the risks and severity of primary or reactivation infections; its prevalence has implications for food and water safety, tuberculosis control, vaccine programs, infection control strategies, outbreak preparedness, travel medicine, and other facets of public health.1 We present data on the prevalence of self-reported immunosuppressed adults in the United States.

Acute respiratory infections among returning Hajj pilgrims—Jordan, 2014

Abstract Background The emergence of Middle East Respiratory Syndrome coronavirus (MERS-CoV) has prompted enhanced surveillance for respiratory infections among pilgrims returning from the Hajj, one of the largest annual mass gatherings in the world. Objectives To describe the epidemiology and etiologies of respiratory illnesses among pilgrims returning to Jordan after the 2014 Hajj. Study design Surveillance for respiratory illness among pilgrims returning to Jordan after the 2014 Hajj was conducted at sentinel health care facilities using epidemiologic surveys and molecular diagnostic testing of upper respiratory specimens for multiple respiratory pathogens, including MERS-CoV. Results Among the 125 subjects, 58% tested positive for at least one virus; 47% tested positive for rhino/enterovirus. No cases of MERS-CoV were detected. Conclusions The majority of pilgrims returning to Jordan from the 2014 Hajj with respiratory illness were determined to have a viral etiology, but none were due to MERS-CoV. A greater understanding of the epidemiology of acute respiratory infections among returning travelers to other countries after Hajj should help optimize surveillance systems and inform public health response practices.

Annual changes in rotavirus hospitalization rates before and after rotavirus vaccine implementation in the United States

Background Hospitalizations for rotavirus and acute gastroenteritis (AGE) have declined in the US with rotavirus vaccination, though biennial peaks in incidence in children aged less than 5 years occur. This pattern may be explained by lower rotavirus vaccination coverage in US children (59% to 73% from 2010–2015), resulting in accumulation of susceptible children over two successive birth cohorts. Methods Retrospective cohort analysis of claims data of commercially insured US children aged <5 years. Age-stratified hospitalization rates for rotavirus and for AGE from the 2002–2015 rotavirus seasons were examined. Median age and rotavirus vaccination coverage for biennial rotavirus seasons during pre-vaccine (2002–2005), early post-vaccine (2008–2011) and late post-vaccine (2012–2015) years. Results Age-stratified hospitalization rates decreased from pre-vaccine to early post-vaccine and then to late post-vaccine years. The clearest biennial pattern in hospitalization rates is the early post-vaccine period, with higher rates in 2009 and 2011 than in 2008 and 2010. The pattern diminishes in the late post-vaccine period. For rotavirus hospitalizations, the median age and the difference in age between biennial seasons was highest during the early post-vaccine period; these differences were not observed for AGE hospitalizations. There was no significant difference in vaccination coverage between biennial seasons. Conclusions These observations provide conflicting evidence that incomplete vaccine coverage drove the biennial pattern in rotavirus hospitalizations that has emerged with rotavirus vaccination in the US. As this pattern is diminishing with higher vaccine coverage in recent years, further increases in vaccine coverage may reach a threshold that eliminates peak seasons in hospitalizations.

Rotavirus Vaccination Is Associated With Reduced Seizure Hospitalization Risk Among Commercially Insured US Children

Rotavirus commonly causes diarrhea but can also cause seizures. Analysis of insurance claims for 1773295 US children with 2950 recorded seizures found that, compared to rotavirus-unvaccinated children, seizure hospitalization risk was reduced by 24% (95% confidence interval [CI], 13%-33%) and 14% (95% CI, 0%-26%) among fully and partially rotavirus-vaccinated children, respectively.

Severe Respiratory Illness Associated with Rhinovirus during the Enterovirus D68 Outbreak in the United States, August 2014-November 2014

Background In 2014, a nationwide outbreak of severe respiratory illness occurred in the United States, primarily associated with enterovirus D68 (EV-D68). A proportion of illness was associated with rhinoviruses (RVs) and other enteroviruses (EVs), which we aimed to characterize further. Methods Respiratory specimens from pediatric and adult patients with respiratory illness were submitted to the Centers for Disease Control and Prevention during August 2014-November 2014. While initial laboratory testing focused on identification of EV-D68, the negative specimens were typed by molecular sequencing to identify additional EV and RV types. Testing for other pathogens was not conducted. We compared available clinical and epidemiologic characteristics among patients with EV-D68 and RV species A-C identified. Results Among 2629 typed specimens, 1012 were EV-D68 (39%) and 81 (3.1%) represented 24 other EV types; 968 were RVs (37%) covering 114 types and grouped into 3 human RV species (RV-A, 446; RV-B, 133; RV-C, 389); and 568 (22%) had no RV or EV detected. EV-D68 was more frequently identified in patients who presented earlier in the investigation period. Among patients with EV-D68, RV-A, RV-B, or RV-C, the age distributions markedly differed. Clinical syndromes and intensive care unit admissions by age were largely similar. Conclusions RVs were commonly associated with severe respiratory illness during a nationwide outbreak of EV-D68, and most clinical. Characteristics were similar between groups. A better understanding of the epidemiology of RVs and EVs is needed to help inform development and use of diagnostic tests, therapeutics, and preventive measures.

Timing of Birth as an Emergent Risk Factor for Rotavirus Hospitalization and Vaccine Performance in the Postvaccination Era in the United States

Rotavirus vaccines were introduced in the United States in 2006, and in the years since they have fundamentally altered the seasonality of rotavirus infection and have shifted disease outbreaks from annual epidemics to biennial epidemics. We investigated whether season and year of birth have emerged as risk factors for rotavirus or have affected vaccine performance. We constructed a retrospective birth cohort of US children under age 5 years using the 2001-2014 MarketScan database (Truven Health Analytics, Chicago, Illinois). We evaluated the associations of season of birth, even/odd year of birth, and interactions with vaccination. We fitted Cox proportional hazards models to estimate the hazard of rotavirus hospitalization according to calendar year of birth and season of birth assessed for interaction with vaccination. After the introduction of rotavirus vaccine, we observed monotonically decreasing rates of rotavirus hospitalization for each subsequent birth cohort but a biennial incidence pattern by calendar year. In the postvaccine period, children born in odd calendar years had a higher hazard of rotavirus hospitalization than those born in even years. Children born in winter had the highest hazard of hospitalization but also had greater vaccine effectiveness than children born in spring, summer, or fall. With the emergence of a strong biennial pattern of disease following vaccine introduction, the timing of a childs birth has become a risk factor for rotavirus infection.

Human Coronavirus Circulation in the USA, 2014‒2017

Abstract Background Human coronaviruses (HCoV) OC43, 229E, NL63 and HKU1 commonly cause upper respiratory tract infections, but can also cause severe lower respiratory tract disease. Increased use of diagnostic assays for respiratory viruses has facilitated detection and, since 2014, voluntary reporting of HCoV to the National Respiratory and Enteric Virus Surveillance System (NREVSS). Methods We reviewed weekly aggregate test results for HCoV OC43, 229E, NL63 and HKU1 voluntarily reported to NREVSS by U.S. hospital and clinical laboratories from July 1, 2014‒April 30, 2017. Laboratories reporting any HCoV result using PCR were included, and the weekly percentage of positive HCoV tests by type was calculated. For a subset of HCoV detections reported to NREVSS via the Public Health laboratory Interoperability Project (PHLIP), which collects individual-level demographic data, we described age distribution and sex. Age distribution by HCoV type was compared using the Kruskal–Wallis test. Results 154 laboratories, across all 9 U.S. census divisions, reported 834,742 tests for HCoV; 18,514 (2.2%) were positive for HCoV-OC43, 8,363 (1.0%) for HCoV-NL63, 6,828 (0.8%) for HCoV-229E, and 5,170 (0.6%) for HCoV-HKU1. The percentage of tests positive for HCoV generally peaked between December and March (Figure 1). HCoV-OC43 showed distinct annual peaks with variation in magnitude by year. HCoV-HKU1 and NL63 had similar patterns, each with notable peaks during winter 2016 compared with 2015 or 2017. HCoV-229E showed a discernable peak in 2017 compared with the previous 2 years. Of 20,533 individuals with HCoV test results reported via PHLIP, 1,589 (7.7%) tested positive for any HCoV; 50% of HCoV-positive individuals were male, and the median age was 22 (range 0–96) years. Age distribution differed between HCoV types (P < 0.01, Figure 2). Conclusion Over approximately 3 seasons, peak positivity for HCoV occurred during winter months, and annual differences in circulation by HCoV type were observed. Continued testing and surveillance for HCoV will allow for further characterization of circulation trends over time and by geographic region, and improved understanding of the contribution of HCoV to the winter respiratory virus season. Disclosures All authors: No reported disclosures.