This week, WAidid suggests "A Measles Outbreak in an Underimmunized Amish Community in Ohio", an article published on NEJM describing epidemiologic features of an outbreak of measles in Ohio and exploring the effect of public health responses on limiting the spread of measles.
Measles is a highly contagious, vaccine-preventable, disease that can lead to serious complications. Although endemic transmission of measles in the United States (U.S.) was declared to be eliminated in 2000, importations from countries in which measles is still endemic continue to occur. The success of the measles-control program in the U.S. is the result of a high rate of coverage with a safe and efficacious vaccine (the measles–mumps–rubella [MMR] vaccine), combined with the aggressive implementation of control measures once cases are detected.
During 2014, the World Health Organization (WHO) reported that there were 21,403 confirmed cases of measles and 110 measles-associated deaths in the Philippines. In March 2014, a measles outbreak was reported in the U.S., after two unvaccinated Amish men had returned to their U.S. communities from the Philippines. The two source patients showed prodromal symptoms (fever, cough, coryza, conjunctivitis), a generalized red maculopapular rash and thrombocytopenia.
During the outbreak, 573 suspected cases of measles were investigated: 190 (33%) were ruled out, which resulted in 383 confirmed cases. The outbreak affected one of the largest Amish settlements in the U.S.: a total of 380 patients (99%) were Amish and 3 case patients (<1%) were non-Amish, but were epidemiologically linked to them. The duration of the outbreak was 121 days. The age distribution of the case patients shifted during the course of the outbreak. Before May 2014 (the approximate midpoint of the outbreak) 26% of the cases occurred among children and adolescents (5 - 17 years of age) and 48% among young adults (18 - 39 years of age); after May 2014, these rates changed to 52% and 25%, respectively (P < 0.001). Diagnostic testing was performed in 69 of the 383 case patients (18%), and measles was confirmed in 57 of the case patients (15%). The virus strain was genotype D9, which was circulating in the Philippines at the time of the reporting period. Before the outbreak, 340 case patients (89%) were unvaccinated. An incident command system was established: 10,644 persons received MMR vaccination, case patients were isolated, and nonimmune persons, who were exposed, were voluntarily quarantined. The authors concluded that the outbreak served as a reminder that measles remains endemic in many countries and that unvaccinated U.S. residents, who return from abroad, continue to place themselves and others at risk for measles. They stressed that communities, that object vaccination, are at increased risk for the spread of measles, while the high baseline vaccination coverage in the general community was probably effective against further spread of measles. The authors reported that measles attack rates were 1.5 to 1.9 times higher among persons younger than 40 years of age, than among those 40 to 54 years of age, which suggests that older age groups had previous natural immunity. Moreover, they stated that unvaccinated young mothers had a high probability of remaining susceptible to measles and therefore they had less possibility to transfer protective antibodies to their neonates.
The authors concluded that earlier recognition of the source of infection might have led to better measles control, highlighting the relevance in identifying the appropriate timing of testing suspected people.
Paul A. Gastañaduy, Jeremy Budd, Nicholas Fisher, Susan B. Redd, Jackie Fletcher, Julie Miller, Dwight J. McFadden, III, Jennifer Rota, Paul A. Rota, Carole Hickman, Brian Fowler, Lilith Tatham, Gregory S. Wallace, Sietske de Fijter, Amy Parker Fiebelkorn, and Mary DiOrio
This week WAidid suggests the article published in September on NEJM "Nasal High-Flow Therapy for Primary Respiratory Support in Preterm Infants", reporting an international, multicenter, randomized, noninferiority trial to test the efficacy of high-flow therapy as the primary means of respiratory support for preterm infants with respiratory distress.
In 2014, there were more than 380,000 preterm births in the United States, accounting for approximately 10% of all births that year. Preterm infants have a risk of the respiratory distress syndrome. Endotracheal ventilation has improved the survival rate, but it is associated with an increased risk of complications, such as bronchopulmonary dysplasia. In presence of respiratory failure, neonatologists aim to use noninvasive respiratory support. The most widely used noninvasive approach, i.e. nasal continuous positive airway pressure (CPAP), has been shown to be an effective alternative to endotracheal ventilation as primary respiratory support for preterm infants. Treatment with heated, humidified, high-flow nasal cannulae (high-flow therapy) is an increasingly popular means of noninvasive respiratory support, which has shown several advantages over CPAP, such as reduced rates of nasal trauma and infant pain scores.
The authors performed an international, multicenter, randomized, controlled trial to test the hypothesis that high-flow therapy would be noninferior to CPAP as primary respiratory support for preterm infants with early respiratory distress. From May 2013 to June 2015, 564 preterm infant out of 583, born at a gestational age of 28 weeks 0 days to 36 weeks 6 days, less than 24 hours old, who had not previously received endotracheal ventilation or surfactant treatment, were randomly assigned to treatment with high-flow therapy or CPAP. Infants were stratified according to gestational age (< 32 weeks vs ≥ 32 weeks). 19 infants were excluded because they did not meet the eligibility criteria or their parents did not provide the consent.The primary outcome was treatment failure within 72 hours after randomization.
The authors concluded that high-flow treatment resulted in a significantly higher rate of treatment failure than CPAP did, when used as primary support (respectively 71 of 278, 25.5% and 38 of 286, 13.3%, P < 0.001). Intubation rates did not differ significantly between the two treatment groups and infants in the high-flow group had a significant lower rate of nasal trauma. However, infants in the high-flow group were more likely to receive brief supplemental oxygen, and the median duration of respiratory support was 1 day longer in this group, although the need of intubation in emergency in the first 72 hours occurred significantly more often in children treated with CPAP and no significant difference was observed in each of the primary outcome.
These results will surely open a huge discussion because other studies concluded with opposite results and authors’ conclusions in this study are not totally convincing on the basis of the results.
AUTHORS: Calum T. Roberts, Louise S. Owen, Brett J. Manley, Dag H. Frøisland, Susan M. Donath, Kim M. Dalziel, Margo A. Pritchard, David W. Cartwright, Clare L. Collins, Atul Malhotra, and Peter G. Davis
To read the article, click here!