A Measles Outbreak in an Underimmunized Amish Community in Ohio

Strategies for Improving Vaccine Communication and Uptake

Vaccines have led to a significant decrease in rates of vaccine-preventable diseases and have made a significant impact on the health of children. However, some parents express concerns about vaccine safety and the necessity of vaccines. The concerns of parents range from hesitancy about some immunizations to refusal of all vaccines. This clinical report provides information about the scope and impact of the problem, the facts surrounding common vaccination concerns, and the latest evidence regarding effective communication techniques for the vaccine conversation. After reading this clinical report, readers can expect to: Understand concepts and underlying determinants of vaccine uptake and vaccine hesitancy.Understand the relationship between vaccine hesitancy and costs of preventable medical care.Recognize and address specific concerns (eg, vaccine safety) with caregivers when hesitancy is present.

Attack rate, case fatality rate and determinants of measles infection during a measles outbreak in Ethiopia: systematic review and meta-analysis

BACKGROUND

Although Ethiopia is working towards measles elimination, a recurrent measles outbreak has occurred. To take appropriate measures, previously, many fragmented and inconsistent outbreak investigations were done, but there is no consolidated evidence on attack rate, case fatality rate, and determinants of measles infection during the measles outbreak. This systematic review and meta-analysis aimed to identify cumulative evidence on attack rate, case fatality rate, and determinants of measles infection during the outbreak.

METHODS

A systematic literature review and Meta-analysis was used. We searched Google Scholar, Medline/PubMed, Cochrane/Wiley Library, EMBASE, Science Direct, and African Journals Online databases using different terms. Investigations that applied any study design, data collection- and analysis methods related to the measles outbreak investigation were included. Data were extracted in an Excel spreadsheet and imported into STATA version 17 software for meta-analysis. The I2 statistics were used to test heterogeneity, and 'Begg's and 'Egger's tests were used to assess publication bias. The odds ratio (OR) with a 95% confidence interval (CI) was presented using forest plots.

RESULTS

Eight measles outbreak investigations with 3004 measles cases and 33 deaths were included in this study. The pooled attack rate (A.R.) and case fatality rate were 34.51/10,000 [95% CI; 21.33-47.70/10,000] population and 2.21% [95% CI; 0.07-2.08%], respectively. Subgroup analysis revealed the highest attack rate of outbreaks in the Oromia region (63.05 per 10,000 population) and the lowest in the Amhara region (17.77 per 10,000 population). Associated factors with the measles outbreak were being unvaccinated (OR = 5.96; 95% CI: 3.28-10.82) and contact history (OR = 3.90; 95% CI: 2.47-6.15).

CONCLUSION

Our analysis revealed compelling evidence within the outbreak descriptions, highlighting elevated attack and case fatality rates. Measles infection was notably linked to being unvaccinated and having a contact history. Strengthening routine vaccination practices and enhancing contact tracing measures are vital strategies moving forward.

Pathways to Immunity: Patterns of Excess Death Across the United States and Within Closed Religious Communities

Public health officials promoted COVID-19 vaccines to limit burdens placed on the U.S. healthcare system and end the pandemic. People in some closed religious communities refused to vaccinate and likely acquired temporary immunity through infection. This paper compares the death rates in Amish, Old Order Mennonites, and conservative Mennonite groups to a rate estimated for the U.S. population. Approximately two-thirds of the U.S. population was immunized against COVID-19, while few in the Amish/Mennonite community were. We find divergent patterns. Once vaccines became available, excess deaths declined in the general population and remained elevated among Amish and Mennonites. Vaccination campaigns must consider and value the cultural beliefs of closed religious communities to be effective.

Measles virus transmission patterns and public health responses during Operation Allies Welcome: a descriptive epidemiological study

BACKGROUND

On Aug 29, 2021, Operation Allies Welcome (OAW) was established to support the resettlement of more than 80 000 Afghan evacuees in the USA. After identification of measles among evacuees, incoming evacuee flights were temporarily paused, and mass measles vaccination of evacuees aged 6 months or older was introduced domestically and overseas, with a 21-day quarantine period after vaccination. We aimed to evaluate patterns of measles virus transmission during this outbreak and the impact of control measures.

METHODS

We conducted a measles outbreak investigation among Afghan evacuees who were resettled in the USA as part of OAW. Patients with measles were defined as individuals with an acute febrile rash illness between Aug 29, 2021, and Nov 26, 2021, and either laboratory confirmation of infection or epidemiological link to a patient with measles with laboratory confirmation. We analysed the demographics and clinical characteristics of patients with measles and used epidemiological information and whole-genome sequencing to track transmission pathways. A transmission model was used to evaluate the effects of vaccination and other interventions.

FINDINGS

47 people with measles (attack rate: 0·65 per 1000 evacuees) were reported in six US locations housing evacuees in four states. The median age of patients was 1 year (range 0-26); 33 (70%) were younger than 5 years. The age distribution shifted during the outbreak towards infants younger than 12 months. 20 (43%) patients with wild-type measles virus had rash onset after vaccination. No fatalities or community spread were identified, nor further importations after flight resumption. In a non-intervention scenario, transmission models estimated that a median of 5506 cases (IQR 10-5626) could have occurred. Infection clusters based on epidemiological criteria could be delineated into smaller clusters using phylogenetic analyses; however, sequences with few substitution count differences did not always indicate single lines of transmission.

INTERPRETATION

Implementation of control measures limited measles transmission during OAW. Our findings highlight the importance of integration between epidemiological and genetic information in discerning between individual lines of transmission in an elimination setting.

FUNDING

US Centers for Disease Control and Prevention.

Modeling vaccination coverage during the 2022 central Ohio measles outbreak: a cross-sectional study

Background

Of the eight large (>50 cases) US postelimination outbreaks, the first and last occurred in Ohio. Ohio's vaccination registry is incomplete. Community-level immunity gaps threaten more than two decades of measles elimination in the US. We developed a statistical model, VaxEstim, to rapidly estimate the early-phase vaccination coverage and immunity gap in the exposed population during the 2022 Central Ohio outbreak.

Methods

We used reconstructed daily incidence (from publicly available data) and assumptions about the distribution of the serial interval, or the time between symptom onset in successive measles cases, to estimate the effective reproduction number (i.e., the average number of secondary infections caused by an infected individual in a partially immune population). We estimated early-phase measles vaccination coverage by comparing the effective reproduction number to the basic reproduction number (i.e., the average number of secondary infections caused by an infected individual in a fully susceptible population) while accounting for vaccine effectiveness. Finally, we estimated the early-phase immunity gap as the difference between the estimated critical vaccination threshold and vaccination coverage.

Findings

VaxEstim estimated the early-phase vaccination coverage as 53% (95% credible interval, 21%-77%), the critical vaccination threshold as 93%, and the immunity gap as 42% (95% credible interval, 18%-74%).

Interpretation

This study estimates a significant immunity gap in the exposed population during the early phase of the 2022 Central Ohio measles outbreak, suggesting a robust public health response is needed to identify the susceptible community and develop community-specific strategies to close the immunity gap.

Funding

This work was supported in part by the National Institute of General Medical Sciences, National Institutes of Health; the UK Medical Research Council (MRC); the Foreign, Commonwealth and Development Office; the National Institute for Health Research (NIHR) Health Protection Research Unit in Modelling Methodology; Imperial College London, and the London School of Hygiene & Tropical Medicine, Community Jameel; the EDCTP2 programme, supported by the EU; and the Sergei Brin Foundation.

Epidemiology of measles in Angola: Results from routine surveillance from 2015 to 2021

Background

Measles, an acute infectious disease of extremely contagious viral aetiology, has been eliminated in some parts of the world. To the best of the authors' knowledge, this is the first study on the epidemiological pattern of the measles virus in Angola, and it was carried out through a review of 7 years of observational retrospective data from the national measles laboratory surveillance programme.

Methods

A retrospective study using national databases on the laboratory surveillance of measles was performed. Patients of all ages with suspected measles from all provinces of Angola were included. Serum samples were used to detect IgM-type measles-virus-specific antibodies by enzyme-linked immunosorbent assay.

Findings

In total, 3690 suspected measles samples were sent to the Instituto Nacional de Investigação em Saúde. There were 962 (26.1%) laboratory-confirmed cases, and the most affected age group was children aged 1-4 years. The highest incidence rate per 100,000 population was found in Benguela (17.9%), followed by Huambo (16.7%) and Cuanza Sul (13.6%). Of the study years, the incidence rate per 1,000,000 population was highest in 2020 (11.9%). The most common complication was diarrhoea (n=406, 42.2%). Of the confirmed cases, 209 (21.7%) were vaccinated, 633 (65.8%) were unvaccinated, and 120 (12.5%) had unknown vaccination status. For all study years, vaccination coverage was <70%.

Interpretation

Measles continues to be a serious problem in Angola, and more efforts are needed to increase measles surveillance and achieve a high percentage of vaccination coverage.

A Structural Lens Approach to Vaccine Hesitancy and Identity

Vaccine hesitancy is an increasing global health threat, and to improve vaccine uptake, it is critical to account for identity-based considerations including racial and ethnic, religious, and contemporary socio-political identities. Using critical consciousness to create awareness of the diverse cultural viewpoints on vaccines can help providers have conversations that are identity aware, equity-focused, and linguistically sensitive with their patients. It is necessary to collaborate with patients, families, communities, and community leaders to share information about vaccines, their safety profiles, and on how to have vaccines readily accessible in each community, to protect children and adolescents against vaccine preventable illnesses.

Physical health conditions of the Amish and intervening social mechanisms: an exhaustive narrative review

As an ethnic religion, the Amish are of interest to population health researchers due to a distinctive health profile arising from ethnic attributes, including a closed genetic pool and shared culture that shapes lifestyle practices. Amish-focused health research both furthers our knowledge of health conditions by comparing Amish with non-Amish and assists health practitioners in serving this rapidly growing population. Amish health research, now representing approximately a quarter of all Amish-focused publications, is in need of review, to the end of strengthening this knowledge body's coherence, clarifying research directions, and identifying knowledge gaps, lapses, and stagnations. Herein, we synthesize and discuss Amish physical health conditions research, both the population's distinctive health profile and mechanisms shaping this profile. Specifically, we summarize research addressing BMI, physical activity, and body image; diet and supplements; cancer; cardiovascular conditions; communicable diseases; immunity; sleep; genetic disorders; tobacco and alcohol use; periodontal conditions; traumatic injuries; natural treatments for burns; fertility; and sexually transmitted diseases. In reflection, we raise questions about the nature of intervening mechanisms shaping the Amish health profile, the strange omission of several common independent variables commonly used when studying other ethnic groups' health, several recurring methodological complications, and public health policy considerations.

Identifying optimal vaccination scenarios to reduce varicella zoster virus transmission and reactivation

BACKGROUND

Varicella zoster virus (VZV) is one of the eight known human herpesviruses. Initial VZV infection results in chickenpox, while viral reactivation following a period of latency manifests as shingles. Separate vaccines exist to protect against both initial infection and subsequent reactivation. Controversy regarding chickenpox vaccination is contentious with most countries not including the vaccine in their childhood immunization schedule due to the hypothesized negative impact on immune-boosting, where VZV reactivation is suppressed through exogenous boosting of VZV antibodies from exposure to natural chickenpox infections.

METHODS

Population-level chickenpox and shingles notifications from Thailand, a country that does not vaccinate against either disease, were previously fitted with mathematical models to estimate rates of VZV transmission and reactivation. Here, multiple chickenpox and shingles vaccination scenarios were simulated and compared to a model lacking any vaccination to analyze the long-term impacts of VZV vaccination.

RESULTS

As expected, simulations suggested that an introduction of the chickenpox vaccine, at any coverage level, would reduce chickenpox incidence. However, chickenpox vaccine coverage levels above 35% would increase shingles incidence under realistic estimates of shingles coverage with the current length of protective immunity from the vaccine. A trade-off between chickenpox and shingles vaccination coverage was discovered, where mid-level chickenpox coverage levels were identified as the optimal target to minimize total zoster burden. Only in scenarios where shingles vaccine provided lifelong immunity or coverage exceeded current levels could large reductions in both chickenpox and shingles be achieved.

CONCLUSIONS

The complicated nature of VZV makes it impossible to select a single vaccination scenario as universal policy. Strategies focused on reducing both chickenpox and shingles incidence, but prioritizing the latter should maximize efforts towards shingles vaccination, while slowly incorporating chickenpox vaccination. Alternatively, countries may wish to minimize VZV complications of both chickenpox and shingles, which would lead to maximizing vaccine coverage levels across both diseases. Balancing the consequences of vaccination to overall health impacts, including understanding the impact of an altered mean age of infection for both chickenpox and shingles, would need to be considered prior to any vaccine introduction.

Rituals of Contagion in Closed Religious Communities: A Case Study of Amish and Mennonite Communities in the USA During the Beginning of the COVID-19 Pandemic

At the onset of the COVID-19 pandemic, government and medical guidelines emphasized social distancing to limit exposure. These guidelines significantly impacted closed religious communities, particularly those opposed to modern technologies, such as Amish and Mennonite communities. How did these religious communities respond to COVID-19 policies in the USA? We draw data from Ohio and Pennsylvania scribe entries published in an Amish/Mennonite correspondence newspaper. While some of these communities altered church rituals to comply with government directives, others maintained communal worship without disruption. Mennonite communities were more likely to conform to guidelines.

Measles Experience, Practice, and Knowledge by Pediatricians in the Context of Resurgent US Outbreaks

OBJECTIVE

To assess measles experience, practice, and knowledge by pediatricians in the context of resurgent US outbreaks in 2018-2019.

STUDY DESIGN

A nationally representative network of pediatricians were surveyed by email and mail from January to April 2020.

RESULTS

The response rate was 67% (297 of 444). In the 3 years preceding the survey, 52% of the respondents reported awareness of measles cases in/near their community. Most thought that media reports about recent measles outbreaks had decreased delay/refusal of measles, mumps, and rubella (MMR) vaccine (6% "greatly decreased"; 66% "moderately decreased"). More than 60% of the pediatricians responded correctly for 6 of 9 true/false measles knowledge items. Less than 50% responded correctly for 3 true/false items, including statements about pretravel MMR recommendations for a preschooler and measles isolation precautions. The most common resources that the pediatricians would "sometimes" or "often/always" consult for measles information were those from the American Academy of Pediatrics (72%), a state or local public health department (70%), and the Centers for Disease Control and Prevention (63%). More than 90% of the pediatricians reported correct clinical practice for MMR vaccination of a 9-month-old before international travel. More than one-third of the respondents did not have a plan for measles exposures in their clinic. Pediatricians aware of measles cases in/near their community in the previous 3 years and those working in a hospital/clinic or Health Maintenance Organization setting were more likely to have a plan for measles exposures.

CONCLUSIONS

During this time of heightened risk for measles outbreaks, there are opportunities to strengthen the knowledge and implementation of measles pretravel vaccination and infection prevention and control recommendations among pediatricians.

Risk Factors for Measles Nonimmunity in Rubella-Immune Pregnant Patients

OBJECTIVES

 Measles immunity testing, unlike that for rubella, is not currently part of prenatal screening even though immunity to both is conferred by the measles-mumps-rubella (MMR) vaccine. Although endemic transmission of measles was declared eliminated in the United States in 2001, outbreaks have continued to occur. Given the risks associated with measles infection during pregnancy, we sought to identify risk factors for measles nonimmunity (MNI) in rubella-immune (RI) pregnant individuals.

METHODS

 We performed a retrospective observational cross-sectional study of patients receiving prenatal care and delivering at two university hospitals and a county hospital in Southern California from April 1, 2019 to February 1, 2021. Inclusion criteria were pregnant individuals ≥18 years old who had serological testing for rubella and measles during pregnancy. Demographic data were extracted from electronic medical records, including results of serological testing and chronic medical conditions. All subjects were rubella immune, and we compared measles-immune (MI) with MNI groups.

RESULTS

 In total, 1,813 RI individuals were identified, with 1,467 (81%) MI and 346 (19%) MNI individuals. Variables associated with an increased risk of MNI included having public health insurance (adjusted relative risk [aRR]: 1.56; 95% confidence interval [CI]: 1.24, 1.97) and Hispanic ethnicity (aRR: 1.37; 95% CI: 1.06, 1.78). Black race was associated with a decreased risk of MNI (aRR: 0.52; 95% CI: 0.29, 0.91). Birth year before 1989 demonstrated a trend toward increased risk of MNI, but this did not reach statistical significance (aRR 1.23; 95% CI: 1.00, 1.52). No differences were seen between the two groups for medical comorbidities.

CONCLUSION

 Our study is the first to demonstrate risk factors for measles MNI in patients with documented rubella immunity. In the absence of universal measles serological screening recommendations, the risk factors identified could help guide clinicians in selective screening for those at risk of needing postpartum MMR vaccination.

KEY POINTS

· The rate of measles nonimmunity is higher than previously reported.. · Hispanic ethnicity and use of public insurance are risk factors for measles nonimmunity.. · The current recommendation for history-based screening for measles immunity is likely insufficient..

Herd immunity and epidemic size in networks with vaccination homophily

We study how the herd immunity threshold and the expected epidemic size depend on homophily with respect to vaccine adoption. We find that the presence of homophily considerably increases the critical vaccine coverage needed for herd immunity and that strong homophily can push the threshold entirely out of reach. The epidemic size monotonically increases as a function of homophily strength for a perfect vaccine, while it is maximized at a nontrivial level of homophily when the vaccine efficacy is limited. Our results highlight the importance of vaccination homophily in epidemic modeling.

The Clinical and Economic Impact of Measles-Mumps-Rubella Vaccinations to Prevent Measles Importations From US Pediatric Travelers Returning From Abroad

BACKGROUND

Pediatric international travelers account for nearly half of measles importations in the United States. Over one third of pediatric international travelers depart the United States without the recommended measles-mumps-rubella (MMR) vaccinations: 2 doses for travelers ≥12 months and 1 dose for travelers 6 to <12 months.

METHODS

We developed a model to compare 2 strategies among a simulated cohort of international travelers (6 months to <6 years): (1) No pretravel health encounter (PHE): travelers depart with baseline MMR vaccination status; (2) PHE: MMR-eligible travelers are offered vaccination. All pediatric travelers experience a destination-specific risk of measles exposure (mean, 30 exposures/million travelers). If exposed to measles, travelers' age and MMR vaccination status determine the risk of infection (range, 3%-90%). We included costs of medical care, contact tracing, and lost wages from the societal perspective. We varied inputs in sensitivity analyses. Model outcomes included projected measles cases, costs, and incremental cost-effectiveness ratios ($/quality-adjusted life year [QALY], cost-effectiveness threshold ≤$100 000/QALY).

RESULTS

Compared with no PHE, PHE would avert 57 measles cases at $9.2 million/QALY among infant travelers and 7 measles cases at $15.0 million/QALY among preschool-aged travelers. Clinical benefits of PHE would be greatest for infants but cost-effective only for travelers to destinations with higher risk for measles exposure (ie, ≥160 exposures/million travelers) or if more US-acquired cases resulted from an infected traveler, such as in communities with limited MMR coverage.

CONCLUSIONS

Pretravel MMR vaccination provides the greatest clinical benefit for infant travelers and can be cost-effective before travel to destinations with high risk for measles exposure or from communities with low MMR vaccination coverage.

The impact of local vaccine coverage and recent incidence on measles transmission in France between 2009 and 2018

BACKGROUND

Subnational heterogeneity in immunity to measles can create pockets of susceptibility and result in long-lasting outbreaks despite high levels of national vaccine coverage. The elimination status defined by the World Health Organization aims to identify countries where the virus is no longer circulating and can be verified after 36 months of interrupted transmission. However, since 2018, numerous countries have lost their elimination status soon after reaching it, showing that the indicators defining elimination may not be associated with lower risks of outbreaks.

METHODS

We quantified the impact of local vaccine coverage and recent levels of incidence on the dynamics of measles in each French department between 2009 and 2018, using mathematical models based on the "Endemic-Epidemic" regression framework. After fitting the models using daily case counts, we simulated the effect of variations in the vaccine coverage and recent incidence on future transmission.

RESULTS

High values of local vaccine coverage were associated with fewer imported cases and lower risks of local transmissions, but regions that had recently reported high levels of incidence were also at a lower risk of local transmission. This may be due to additional immunity accumulated during recent outbreaks. Therefore, the risk of local transmission was not lower in areas fulfilling the elimination criteria. A decrease of 3% in the 3-year average vaccine uptake led to a fivefold increase in the average annual number of cases in simulated outbreaks.

CONCLUSIONS

Local vaccine uptake was a reliable indicator of the intensity of transmission in France, even if it only describes yearly coverage in a given age group, and ignores population movements. Therefore, spatiotemporal variations in vaccine coverage, caused by disruptions in routine immunisation programmes, or lower trust in vaccines, can lead to large increases in both local and cross-regional transmission. The incidence indicator used to define the elimination status was not associated with a lower number of local transmissions in France, and may not illustrate the risks of imminent outbreaks. More detailed models of local immunity levels or subnational seroprevalence studies may yield better estimates of local risk of measles outbreaks.

Maintenance of measles elimination status in the United States for 20 years despite increasing challenges

BACKGROUND

Measles elimination (interruption of endemic measles virus transmission) in the United States was declared in 2000; however, the number of cases and outbreaks have increased in recent years. We characterized the epidemiology of measles outbreaks and measles transmission patterns post-elimination to identify potential gaps in the U.S. measles control program.

METHODS

We analyzed national measles notification data from January 1, 2001-December 31, 2019. We defined measles infection clusters as single cases (isolated cases not linked to additional cases), 2-case clusters, or outbreaks with 3 or more linked cases. We calculated the effective reproduction number (R) to assess changes in transmissibility and reviewed molecular epidemiology data.

RESULTS

During 2001-2019, 3,873 measles cases, including 747 international importations, were reported in the United States; 29% of importations were associated with outbreaks. Among 871 clusters, 69% were single cases and 72% had no spread. Larger and longer clusters were reported since 2013, including seven outbreaks with >50 cases lasting >2 months, 5 of which occurred in known underimmunized, close-knit communities. No measles lineage circulated in a single transmission chain for >12 months. Higher estimates of R were noted in recent years, although R remained below the epidemic threshold of 1.

CONCLUSIONS

Current epidemiology continues to support the interruption of endemic measles virus transmission in the United States. However, larger and longer outbreaks in recent post-elimination years and emerging trends of increased transmission in underimmunized communities emphasize the need for targeted approaches to close existing immunity gaps and maintain measles elimination.

Closed but Not Protected: Excess Deaths Among the Amish and Mennonites During the COVID-19 Pandemic

"Excess deaths" is a means to estimate the lethality of COVID-19 (directly and indirectly). Assessing "excess death" in closed religious communities provides information on how COVID-19 impacted these communities. We use obituary information published in an Amish/Mennonite newspaper to examine excess death among the Amish/Mennonites in 2020. Our results indicate the Amish/Mennonite excess death rates are similar to the national trends in the USA. The excess death rate for Amish/Mennonites spiked with a 125% increase in November 2020. The impact of COVID-19 on this closed religious community highlights the need to consider religion to stop the spread of COVID-19.

When measles came to class: a look back at the 1989 Kent State University measles epidemic

BACKGROUND

Measles was eliminated from the United States in 2000, following a change from a single dose of measles vaccine to two doses after an epidemic 1989-1991. Several college campuses experienced outbreaks, including Kent State University (KSU) in Ohio.

METHODS

Local news media from 1988-1989 were searched in August 2019. Interventions taken by the university were recorded, and an epidemic curve constructed.

RESULTS

The first measles cases were reported in October 1988. The outbreak diminished over winter break. New cases were confirmed in February 1989. Infected students were instructed to vacate the dorms. Vaccines were mandated for student groups. The epidemic grew rapidly in March but slowed after spring break. By April, 380 cases had been reported and 7000 students vaccinated.

CONCLUSIONS

KSU was one of the hardest-hit universities during the 1989 measles epidemic. A combination of vaccination, isolation, quarantine, and elimination of public events helped to curtail the epidemic.

‘When the Waves Roll High’: Religious Coping among the Amish and Mennonites during the COVID-19 Pandemic

Religious beliefs, practices, and social support facilitate coping with psychologically distressful events and circumstances. However, COVID-19 and governmental mandates for social distancing and isolation make in-person communal forms of religious coping difficult. While some congregations began holding virtual rituals, this was not an option for Amish and conservative Mennonite groups that restrict communication and media technologies as a religious sacrament. Governmental mandates placed a disproportionate burden on these groups whose members could not conduct rituals or interact virtually with other members and family. What religious coping strategies did the Amish and Mennonites use to cope with the COVID-19 pandemic given their restricted ability to participate in in-person rituals? We collected data from The Budget and The Diary, two Amish and Mennonite correspondence newspapers, which provide information on the experiences of community members. We content analyzed all entries from March 2020 to April 2020 and identified several themes related to religious coping focused on the positive benefits of the pandemic, specifically how it helps and reminds the Amish and Mennonites to refocus on the simple and important things in life, including God, spirituality, family, tradition, gardening, and other at-home hobbies, all of which reflect their religious commitment to a slower pace of life.

o2geosocial: Reconstructing who-infected-whom from routinely collected surveillance data

Reconstructing the history of individual transmission events between cases is key to understanding what factors facilitate the spread of an infectious disease. Since conducting extended contact-tracing investigations can be logistically challenging and costly, statistical inference methods have been developed to reconstruct transmission trees from onset dates and genetic sequences. However, these methods are not as effective if the mutation rate of the virus is very slow, or if sequencing data is sparse. We developed the package o2geosocial to combine variables from routinely collected surveillance data with a simple transmission process model. The model reconstructs transmission trees when full genetic sequences are unavailable, or uninformative. Our model incorporates the reported age-group, onset date, location and genotype of infected cases to infer probabilistic transmission trees. The package also includes functions to summarise and visualise the inferred cluster size distribution. The results generated by o2geosocial can highlight regions where importations repeatedly caused large outbreaks, which may indicate a higher regional susceptibility to infections. It can also be used to generate the individual number of secondary transmissions, and show the features associated with individuals involved in high transmission events. The package is available for download from the Comprehensive R Archive Network (CRAN) and GitHub.

[Geographic analyses as a foundation for evidence-based public health interventions: the example identification and typology of risk clusters for mumps, measles, and rubella]

BACKGROUND

Ideally, health services and interventions to improve immunization rates should be tailored to local target populations, such as spatial clusters. However, to date, little attention has been paid to spatial clusters of underimmunization and have instead been typified based on small-scale data.

AIM

Using the example of vaccination against measles, mumps, and rubella (MMR) in children, the present study aims to (1) identify the spatial distribution of insufficient MMR vaccination in Westphalia-Lippe on a small scale, (2) identify specific, spatial risk clusters with insufficient vaccination protection, and (3) describe spatial-neighborhood influencing factors of the different risk clusters as starting points for public health interventions.

MATERIAL AND METHODS

Account data from the Kassenärztliche Vereinigung Westfalen-Lippe (KVWL) were used as a basis. Birth cohorts 2013-2016 of children with statutory health insurance were formed and aggregated at postcode level (n = 410). Statistically significant, spatially compact clusters and relative risks (RRs) of underimmunization were identified. Local risk models were estimated in binary logistic regressions based on spatial-neighborhood variables.

RESULTS AND DISCUSSION

Two significant clusters of underimmunization were identified for each of the vaccination rates "at least one MMR vaccination" and "both MMR vaccinations." Significant risk factors for low immunization rates included age structure, socioeconomic variables, population density, medical coverage, and value attitude. The proposed methodology is suitable for describing spatial variations in vaccination behavior based on identified typologies for targeted evidence-based interventions.

Outbreak response operations during the US measles epidemic, 2017-19

BACKGROUND

To understand operational challenges involved with responding to US measles outbreaks in 2017-19 and identify applicable lessons in order to inform preparedness and response operations for future outbreaks, particularly with respect to specific operational barriers and recommendations for outbreak responses among insular communities.

METHODS

From August 2019 to January 2020, we conducted 11 telephone interviews with 18 participants representing state and local health departments and community health centers that responded to US measles outbreaks in 2017-19, with a focus on outbreaks among insular communities. We conducted qualitative, thematic coding to identify and characterize key operational challenges and lessons identified by the interviewees.

RESULTS

We categorized principal insights into 5 topic areas: scale of the response, vaccination operations, exclusion policies, community engagement, and countering anti-vaccine efforts. These topics address resource-intensive aspects of these outbreak responses, including personnel demands; guidance needed to support response operations and reduce transmission, such as excluding exposed or at-risk individuals from public spaces; operational challenges and barriers to vaccination and other response activities; and effectively engaging and educating affected populations, particularly with respect to insular and vulnerable communities.

CONCLUSIONS

Measles outbreak responses are resource intensive, which can quickly overwhelm existing public health capacities. Early and effective coordination with trusted leaders and organizations in affected communities, including to provide vaccination capacity and facilitate community engagement, can promote efficient response operations. The firsthand experiences of public health and healthcare personnel who responded to measles outbreaks, including among insular communities, provide evidence-based operational lessons that can inform future preparedness and response operations for outbreaks of highly transmissible diseases.

Societal Costs of a Measles Outbreak

BACKGROUND AND OBJECTIVES

Between December 31, 2018, and April 26, 2019, 72 confirmed cases of measles were identified in Clark County. Our objective was to estimate the economic burden of the measles outbreak from a societal perspective, including public health response costs as well as direct medical costs and productivity losses of affected individuals.

METHODS

To estimate costs related to this outbreak from the societal perspective, 3 types of costs were collected or estimated: public health response (labor, material, and contractor costs used to contain the outbreak), direct medical (third party or patient out-of-pocket treatment costs of infected individuals), and productivity losses (costs of lost productivity due to illness, home isolation, quarantine, or informal caregiving).

RESULTS

The overall societal cost of the 2019 Clark County measles outbreak was ∼$3.4 million ($47 479 per case or $814 per contact). The majority of the costs (∼$2.3 million) were incurred by the public health response to the outbreak, followed by productivity losses (∼$1.0 million) and direct medical costs (∼$76 000).

CONCLUSIONS

Recent increases in incident measles cases in the United States and across the globe underscore the need to more fully understand the societal cost of measles cases and outbreaks and economic consequences of undervaccination. Our estimates can provide valuable inputs for policy makers and public health stakeholders as they consider budget determinations and the substantial value associated with increasing vaccine coverage and outbreak preparedness as well as the protection of society against vaccine-preventable diseases, such as measles, which are readily preventable with high vaccination coverage.

Vaccination patterns of the northeast Ohio Amish revisited

OBJECTIVES

The Holmes County Amish have low vaccination rates, an increasingly diverse population, and have an increased incidence of certain inherited diseases. The objectives were to evaluate; the rate and influences of vaccine hesitancy compared to a decade ago, vaccination patterns between Amish affiliations, vaccine practices of Amish special needs children, and the Amish's acceptance of a COVID-19 vaccine.

STUDY DESIGN

In April of 2020, a survey assessing vaccination patterns and beliefs were mailed to 1000 Amish families, including ultra-conservative Amish sects and special needs families.

RESULTS

The response rate was 39%. Among 391 respondents, 59% did not vaccinate their children, compared to only 14% that refused all vaccinations reported by Wenger et al in the same community only a decade ago. The ultra-conservative Amish rejected vaccines more often. Amish special needs children were more likely to receive vaccines than healthy Amish children. 75% responded they would reject a COVID-19 vaccine. Fear of adverse effects was the most common reason to reject vaccines. Families that accepted vaccines were more likely to cite a healthcare worker as the primary influence to vaccinate. Wives were more likely to cite their spouse as the primary influence to vaccinate. Families that rejected vaccines were more likely to state their bishop was the most influential person on vaccination.

CONCLUSION

The Holmes County Amish have decreasing vaccine acceptance. Efforts to improve vaccination will require a targeted focus on the primary influences and beliefs of sub-populations within the Amish. Physician advocacy, peer mentorship, father-directed education, and close partnership with Church leadership will be needed to limit vaccine-preventable disease. The Amish may be at risk for low uptake of a COVID-19 vaccine.

COVID-19 Outbreak in an Amish Community - Ohio, May 2020

In the United States, outbreaks of SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19), were initially reported in densely populated urban areas (1); however, outbreaks have since been reported in rural communities (2,3). Rural residents might be at higher risk for severe COVID-19-associated illness because, on average, they are older, have higher prevalences of underlying medical conditions, and have more limited access to health care services.* In May, after a cluster of seven COVID-19 cases was identified in a rural Ohio Amish community, access to testing was increased. Among 30 additional residents tested by real-time reverse transcription-polymerase chain reaction (RT-PCR; TaqPath COVID-19 Combo Kit),^† 23 (77%) received positive test results for SARS-CoV-2. Rapid and sustained transmission of SARS-CoV-2 was associated with multiple social gatherings. Informant interviews revealed that community members were concerned about having to follow critical mitigation strategies, including social distancing^§ and mask wearing.^¶ To help reduce the ongoing transmission risk in a community, state and county health department staff members and community leaders need to work together to develop, deliver, and promote culturally responsive health education messages to prevent SARS-CoV-2 transmission and ensure that access to testing services is timely and convenient. Understanding the dynamics of close-knit communities is crucial to reducing SARS-CoV-2 transmission.

The Amish health culture and culturally sensitive health services: An exhaustive narrative review

As the Amish population is growing, researcher and practitioner interest in the Amish health culture is also growing. This is largely due to demand from practitioners for population-specific cultural guidance. Once a small area of study, health-themed publications in Amish studies (n = 246) now account for approximately one-fourth of all peer-reviewed publications, and a sizeable percentage address the health culture, i.e. Amish beliefs, practices, attitudes, decision-making processes, financing, and values. In this article, we provide a first-ever exhaustive narrative review of the Amish health culture literature (addressing Amish health conditions elsewhere). Specifically, we address Amish use of modern medicine, complementary & alternative medicine, cultural norms for birthing and intercourse, support and care for the sick and aged, health knowledge, payment for services, barriers to service access, service provider effectiveness, health programming, and ethical conflicts. Our goal is to organize the literature, synthesize findings, identify orienting perspectives, and clarify research questions and directions. Following our synthesis, we reflect on the current state of Amish health culture research, drawing particular attention to strengths and limitations of the oft-used cultural competency paradigm, and recommending more rigorous social scientific theorization of the Amish health culture.

Fine-scale spatial clustering of measles nonvaccination that increases outbreak potential is obscured by aggregated reporting data

The United States experienced historically high numbers of measles cases in 2019, despite achieving national measles vaccination rates above the World Health Organization recommendation of 95% coverage with two doses. Since the COVID-19 pandemic began, resulting in suspension of many clinical preventive services, pediatric vaccination rates in the United States have fallen precipitously, dramatically increasing risk of measles resurgence. Previous research has shown that measles outbreaks in high-coverage contexts are driven by spatial clustering of nonvaccination, which decreases local immunity below the herd immunity threshold. However, little is known about how to best conduct surveillance and target interventions to detect and address these high-risk areas, and most vaccination data are reported at the state-level-a resolution too coarse to detect community-level clustering of nonvaccination characteristic of recent outbreaks. In this paper, we perform a series of computational experiments to assess the impact of clustered nonvaccination on outbreak potential and magnitude of bias in predicting disease risk posed by measuring vaccination rates at coarse spatial scales. We find that, when nonvaccination is locally clustered, reporting aggregate data at the state- or county-level can result in substantial underestimates of outbreak risk. The COVID-19 pandemic has shone a bright light on the weaknesses in US infectious disease surveillance and a broader gap in our understanding of how to best use detailed spatial data to interrupt and control infectious disease transmission. Our research clearly outlines that finer-scale vaccination data should be collected to prevent a return to endemic measles transmission in the United States.

The Clinical Impact and Cost-effectiveness of Measles-Mumps-Rubella Vaccination to Prevent Measles Importations Among International Travelers From the United States

BACKGROUND

Measles importations and the subsequent spread from US travelers returning from abroad are responsible for most measles cases in the United States. Increasing measles-mumps-rubella (MMR) vaccination among departing US travelers could reduce the clinical impact and costs of measles in the United States.

METHODS

We designed a decision tree to evaluate MMR vaccination at a pretravel health encounter (PHE), compared with no encounter. We derived input parameters from Global TravEpiNet data and literature. We quantified Riskexposure to measles while traveling and the average number of US-acquired cases and contacts due to a measles importation. In sensitivity analyses, we examined the impact of destination-specific Riskexposure, including hot spots with active measles outbreaks; the percentage of previously-unvaccinated travelers; and the percentage of travelers returning to US communities with heterogeneous MMR coverage.

RESULTS

The no-encounter strategy projected 22 imported and 66 US-acquired measles cases, costing $14.8M per 10M travelers. The PHE strategy projected 15 imported and 35 US-acquired cases at $190.3M per 10M travelers. PHE was not cost effective for all international travelers (incremental cost-effectiveness ratio [ICER] $4.6M/measles case averted), but offered better value (ICER <$100 000/measles case averted) or was even cost saving for travelers to hot spots, especially if travelers were previously unvaccinated or returning to US communities with heterogeneous MMR coverage.

CONCLUSIONS

PHEs that improve MMR vaccination among US international travelers could reduce measles cases, but are costly. The best value is for travelers with a high likelihood of measles exposure, especially if the travelers are previously unvaccinated or will return to US communities with heterogeneous MMR coverage.

Probabilistic reconstruction of measles transmission clusters from routinely collected surveillance data

Pockets of susceptibility resulting from spatial or social heterogeneity in vaccine coverage can drive measles outbreaks, as cases imported into such pockets are likely to cause further transmission and lead to large transmission clusters. Characterizing the dynamics of transmission is essential for identifying which individuals and regions might be most at risk. As data from detailed contact-tracing investigations are not available in many settings, we developed an R package called o2geosocial to reconstruct the transmission clusters and the importation status of the cases from their age, location, genotype and onset date. We compared our inferred cluster size distributions to 737 transmission clusters identified through detailed contact-tracing in the USA between 2001 and 2016. We were able to reconstruct the importation status of the cases and found good agreement between the inferred and reference clusters. The results were improved when the contact-tracing investigations were used to set the importation status before running the model. Spatial heterogeneity in vaccine coverage is difficult to measure directly. Our approach was able to highlight areas with potential for local transmission using a minimal number of variables and could be applied to assess the intensity of ongoing transmission in a region.

An Update and Review of Measles for Emergency Physicians

BACKGROUND

It is vital for frontline emergency physicians to immediately recognize the signs and symptoms of measles to initiate appropriate therapy and prevent spread to the health care team and other patients.

OBJECTIVE

This review serves as a clinically practical updated reference for when the differential diagnosis includes measles.

DISCUSSION

Measles is a highly contagious illness that classically presents with a rash, fever, cough, coryza, and conjunctivitis. Cases in the United States since 2000 have been attributed mainly to travelers who are infected abroad and then spread the illness to small, susceptible populations within the United States. Complications from measles are relatively common and can be associated with significant morbidity and mortality. Clinical suspicion should be confirmed with laboratory testing, which is most commonly a serum immunoglobulin M. The management of measles is mainly supportive. Patients that require more aggressive management include those who are pregnant, immunocompromised, or unvaccinated. Treatment may consist of the measles vaccine, intravenous immunoglobulin, vitamin A, and even ribavirin. Additionally, special precautions are required by hospital workers to help prevent the spread of the virus, which include N-95 masks and patient isolation in an airborne infection isolation room.

CONCLUSION

Emergency physicians must be readily able to identify, contain patients with suspected measles, and determine who will need further medical management for this potentially life-threatening illness. As this public health crisis evolves, novel ways of screening for and reporting cases of measles is needed.

Clinical Practices for Measles-Mumps-Rubella Vaccination Among US Pediatric International Travelers

IMPORTANCE

The US population is experiencing a resurgence of measles, with more than 1000 cases during the first 6 months of 2019. Imported measles cases among returning international travelers are the source of most US measles outbreaks, and these importations can be reduced with pretravel measles-mumps-rubella (MMR) vaccination of pediatric travelers. Although it is estimated that children account for less than 10% of US international travelers, pediatric travelers account for 47% of all known measles importations.

OBJECTIVE

To examine clinical practice regarding MMR vaccination of pediatric international travelers and to identify reasons for nonvaccination of pediatric travelers identified as MMR eligible.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study of pediatric travelers (ages ≥6 months and <18 years) attending pretravel consultation at 29 sites associated with Global TravEpiNet (GTEN), a Centers for Disease Control and Prevention-supported consortium of clinical sites that provide pretravel consultations, was performed from January 1, 2009, through December 31, 2018.

MAIN OUTCOMES AND MEASURES

Measles-mumps-rubella vaccination among MMR vaccination-eligible pediatric travelers.

RESULTS

Of 14 602 pretravel consultations for pediatric international travelers, 2864 travelers (19.6%; 1475 [51.5%] males; 1389 [48.5%] females) were eligible to receive pretravel MMR vaccination at the time of the consultation: 365 of 398 infants aged 6 to 12 months (91.7%), 2161 of 3623 preschool-aged travelers aged 1 to 6 years (59.6%), and 338 of 10 581 school-aged travelers aged 6 to 18 years (3.2%). Of 2864 total MMR vaccination-eligible travelers, 1182 (41.3%) received the MMR vaccine and 1682 (58.7%) did not. The MMR vaccination-eligible travelers who did not receive vaccine included 161 of 365 infants (44.1%), 1222 of 2161 preschool-aged travelers (56.5%), and 299 of 338 school-aged travelers (88.5%). We observed a diversity of clinical practice at different GTEN sites. In multivariable analysis, MMR vaccination-eligible pediatric travelers were less likely to be vaccinated at the pretravel consultation if they were school-aged (model 1: odds ratio [OR], 0.32 [95% CI, 0.24-0.42; P < .001]; model 2: OR, 0.26 [95% CI, 0.14-0.47; P < .001]) or evaluated at specific GTEN sites (South: OR, 0.06 [95% CI, 0.01-0.52; P < .001]; West: OR, 0.10 [95% CI, 0.02-0.47; P < .001]). The most common reasons for nonvaccination were clinician decision not to administer MMR vaccine (621 of 1682 travelers [36.9%]) and guardian refusal (612 [36.4%]).

CONCLUSIONS AND RELEVANCE

Although most infant and preschool-aged travelers evaluated at GTEN sites were eligible for pretravel MMR vaccination, only 41.3% were vaccinated during pretravel consultation, mostly because of clinician decision or guardian refusal. Strategies may be needed to improve MMR vaccination among pediatric travelers and to reduce measles importations and outbreaks in the United States.

Influenza, Measles, SARS, MERS, and Smallpox

Influenza, measles, SARS, MERS, and smallpox illnesses are caused by highly infectious viral pathogens that induce critical illness. These biologically diverse viruses enter and replicate within host cells triggering viral- and host-mediated damage that results in pneumonia and multiorgan failure in severe cases. Early case identification and strict infection control limit healthcare transmission. Vaccination allowed smallpox eradication and limits global measles and seasonal influenza mortality. While SARS-coronavirus (CoV) is no longer circulating, MERS-CoV and zoonotic influenza viruses, with pandemic potential, remain persistent threats. Supportive critical care is the mainstay of treatment for severe disease due to these viral infections.

Factors Associated With Measles Transmission in the United States During the Postelimination Era

IMPORTANCE

Measles cases and outbreaks continue to occur in the United States after the introduction of measles from endemic settings.

OBJECTIVE

To discern the factors associated with measles transmission in the United States after measles had been eliminated.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study was conducted from January 1, 2001, to December 31, 2017, in the United States among US residents and international visitors with confirmed measles. A maximum likelihood algorithm that uses the observed dates of rash onset and the known distribution of the serial interval (time between symptom onset in related consecutive cases) was applied to outbreak notification data to estimate the effective reproduction number (R), or the mean number of new infections generated per case. Transmissibility was assessed by comparing R based on the characteristics of primary and secondary cases of measles.

EXPOSURES

Measles virus.

MAIN OUTCOMES AND MEASURES

Effective reproduction number (R), or the mean number of successful transmission events per case of measles (ie, the mean number of persons to whom each patient with measles spreads measles).

RESULTS

A total of 2218 individuals with confirmed measles cases (1025 female, 1176 male, and 17 sex not reported; median age, 15 years [range, 0-89 years]) reported from 2001 to 2017 were evaluated. Among patients who received no doses of measles vaccine, R was 0.76 (95% CI, 0.71-0.81); among patients who received 1 dose of measles vaccine, R was 0.17 (95% CI, 0.11-0.26); among patients who received 2 doses or more of measles vaccine, R was 0.27 (95% CI, 0.17-0.39); and among patients with unknown vaccination status, R was 0.52 (95% CI, 0.44-0.60). Among patients born before 1957, R was 0.35 (95% CI, 0.20-0.58), and among those born on or after 1957, R was 0.64 (95% CI, 0.61-0.68). R was higher when primary and secondary cases of measles were patients aged 5 to 17 years (0.36 [95% CI, 0.31-0.42]) compared with assortative transmission in other age groups (<1 year, 0.14 [95% CI, 0.10-0.20]; 1-4 years, 0.25 [95% CI, 0.20-0.30]; 18-29 years, 0.19 [95% CI, 0.15-0.24]; 30-49 years, 0.15 [95% CI, 0.11-0.20]; ≥50 years, 0.04 [95% CI, 0.01-0.10]).

CONCLUSIONS AND RELEVANCE

The findings of this study support having high targets for 2-dose measles vaccine coverage, particularly among school-aged children in the United States.

Measles outbreak in an office building in the crowded Metropolis of Beijing, China

Background

Although worldwide measles elimination achieved great progress for decades, outbreaks were still reported in certain countries. This study describes the epidemiologic features of a substantial measles outbreak in an office building in Beijing and explores control strategies in a crowded city.

Methods

We performed descriptive analyses of data on demographic characteristic, laboratory testing and epidemiological information.

Results

From February 25 to March 28, 2016, 43 outbreak-related measles cases occurred in an office building in Beijing. The total crude attack rate was 1.20% in the building. The age range of patients was 23 to 45 years old, of whom 30 (69.8%) were migrants and 5 (11.6%) were vaccinated but without documentation. The attack rate of the department and the company of the source case was 22.73 and 11.86%, respectively. The attack rate in the building was 1.78%, except for the commercial center on the lower floors, which was 0.34%. Of the 43 measles cases, only 19 cases (53.5%) were reported by hospitals through the National Notifiable Disease Reporting System (NNDRS), and the rest were found through active surveillance. Outbreak response immunization was conducted for 6216 persons.

Conclusions

Office buildings in crowded metropolis are prone to large-scale measles outbreaks, and require a rapid outbreak response. Early Outbreak response immunization and active surveillance are important strategies to control outbreaks such as the one reported herein.

Forecasted Size of Measles Outbreaks Associated With Vaccination Exemptions for Schoolchildren

IMPORTANCE

Vaccine exemptions, which allow unvaccinated children to attend school, have increased by a factor of 28 since 2003 in Texas. Geographic clustering of unvaccinated children facilitates the spread of measles introductions, but the potential size of outbreaks is unclear.

OBJECTIVE

To forecast the range of measles outbreak sizes in each metropolitan area of Texas at 2018 and future reduced school vaccination rates.

DESIGN, SETTING, AND PARTICIPANTS

An agent-based decision analytical model using a synthetic population of Texas, derived from the 2010 US Census, was used to simulate measles transmission in the Texas population. Real schools were represented in the simulations, and the 2018 vaccination rate of each real school was applied to a simulated hypothetical equivalent. Single cases of measles were introduced, daily activities and interactions were modeled for each population member, and the number of infections over the course of 9 months was counted for 1000 simulated runs in each Texas metropolitan area.

INTERVENTIONS

To determine the outcomes of further decreases in vaccination coverage, additional simulations were performed with vaccination rates reduced by 1% to 10% in schools with populations that are currently undervaccinated.

MAIN OUTCOMES AND MEASURES

Expected distributions of outbreak sizes in each metropolitan area of Texas at 2018 and reduced vaccination rates.

RESULTS

At 2018 vaccination rates, the median number of cases in large metropolitan areas was typically small, ranging from 1 to 3 cases, which is consistent with outbreaks in Texas 2006 to 2017. However, the upper limit of the distribution of plausible outbreaks (the 95th percentile, associated with 1 in 20 measles introductions) exceeded 400 cases in both the Austin and Dallas metropolitan areas, similar to the largest US outbreaks since measles was eliminated in 2000. Decreases in vaccination rates in schools with undervaccinated populations in 2018 were associated with exponential increases in the potential size of outbreaks: a 5% decrease in vaccination rate was associated with a 40% to 4000% increase in potential outbreak size, depending on the metropolitan area. A mean (SD) of 64% (11%) of cases occurred in students for whom a vaccine had been refused, but a mean (SD) of 36% (11%) occurred in others (ie, bystanders).

CONCLUSIONS AND RELEVANCE

This study suggests that vaccination rates in some Texas schools are currently low enough to allow large measles outbreaks. Further decreases are associated with dramatic increases in the probability of large outbreaks. Limiting vaccine exemptions could be associated with a decrease in the risk of large measles outbreaks.

Assessing Zika Virus Transmission Within Households During an Outbreak in Martinique, 2015-2016

Since 2015, Zika virus (ZIKV) has caused large epidemics in the Americas. Households are natural targets for control interventions, but quantification of the contribution of household transmission to overall spread is needed to guide policy. We developed a modeling framework to evaluate this contribution and key epidemic features of the ZIKV epidemic in Martinique in 2015-2016 from the joint analysis of a household transmission study (n = 68 households), a study among symptomatic pregnant women (n = 281), and seroprevalence surveys of blood donors (n = 457). We estimated that the probability of mosquito-mediated within-household transmission (from an infected member to a susceptible one) was 21% (95% credible interval (CrI): 5, 51), and the overall probability of infection from outside the household (i.e., in the community) was 39% (95% CrI: 27, 50). Overall, 50% (95% CrI: 43, 58) of the population was infected, with 22% (95% CrI: 5, 46) of infections acquired in households and 40% (95% CrI: 23, 56) being asymptomatic. The probability of presenting with Zika-like symptoms due to another cause was 16% (95% CrI: 10, 23). This study characterized the contribution of household transmission in ZIKV epidemics, demonstrating the benefits of integrating multiple data sets to gain more insight into epidemic dynamics.

Increase in Measles Cases - United States, January 1-April 26, 2019

As of April 26, 2019, CDC had reported 704 cases of measles in the United States since the beginning of 2019, representing the largest number of cases reported in the country in a single year since 1994, when 963 cases occurred, and since measles was declared eliminated* in 2000 (1,2). Measles is a highly contagious, acute viral illness characterized by fever and a maculopapular rash; complications include pneumonia, encephalitis, and death. Among the 704 cases, 503 (71%) were in unvaccinated persons and 689 (98%) occurred in U.S. residents. Overall, 66 (9%) patients were hospitalized. Thirteen outbreaks have been reported in 2019, accounting for 663 cases, 94% of all reported cases. Six of the 13 outbreaks were associated with underimmunized close-knit communities and accounted for 88% of all cases. High 2-dose measles vaccination coverage in the United States has been critical to limiting transmission (3). However, increased global measles activity poses a risk to U.S. elimination, particularly when unvaccinated travelers acquire measles abroad and return to communities with low vaccination rates (4). Health care providers should ensure persons are up to date with measles, mumps, rubella (MMR) vaccine, including before international travel, and rapidly report all suspected cases of measles to public health authorities.

Characterizing the impact of spatial clustering of susceptibility for measles elimination

Measles elimination efforts are primarily focused on achieving and maintaining national vaccination coverage goals, based on estimates of the critical vaccination threshold (Vc): the proportion of the population that must be immune to prevent sustained epidemics. Traditionally, Vc estimates assume evenly mixing populations, an invalid assumption. If susceptible individuals preferentially contact one another, communities may remain vulnerable to epidemics even when vaccination coverage targets are met at the national level. Here we present a simple method to estimate Vc and the effective reproductive number, R, while accounting for spatial clustering of susceptibility. For measles, assuming R0 = 15 and 95% population immunity, adjustment for high clustering of susceptibility increases R from 0.75 to 1.29, Vc from 93% to 96%, and outbreak probability after a single introduction from <1% to 23%. The impact of clustering remains minimal until vaccination coverage nears elimination levels. We illustrate our approach using Demographic and Health Survey data from Tanzania and show how non-vaccination clustering potentially contributed to continued endemic transmission of measles virus during the last two decades. Our approach demonstrates why high national vaccination coverage sometimes fails to achieve measles elimination, and that a shift from national to subnational focus is needed as countries approach elimination.

Nonhuman Primate Models of Respiratory Disease: Past, Present, and Future

The respiratory system consists of an integrated network of organs and structures that primarily function for gas exchange. In mammals, oxygen and carbon dioxide are transmitted through a complex respiratory tract, consisting of the nasal passages, pharynx, larynx, and lung. Exposure to ambient air throughout the lifespan imposes vulnerability of the respiratory system to environmental challenges that can contribute toward development of disease. The importance of the respiratory system to human health is supported by statistics from the Centers for Disease Control and Prevention; in 2015, chronic lower respiratory diseases were the third leading cause of death in the United States. In light of the significant mortality associated with respiratory conditions that afflict all ages of the human population, this review will focus on basic and preclinical research conducted in nonhuman primate models of respiratory disease. In comparison with other laboratory animals, the nonhuman primate lung most closely resembles the human lung in structure, physiology, and mucosal immune mechanisms. Studies defining the influence of inhaled microbes, pollutants, or allergens on the nonhuman primate lung have provided insight on disease pathogenesis, with the potential for elucidation of molecular targets leading to new treatment modalities. Vaccine trials in nonhuman primates have been crucial for confirmation of safety and protective efficacy against infectious diseases of the lung in a laboratory animal model that recapitulates pathology observed in humans. In looking to the future, nonhuman primate models of respiratory diseases will continue to be instrumental for translating biomedical research for improvement of human health.

Quantifying the impact of social groups and vaccination on inequalities in infectious diseases using a mathematical model

BACKGROUND

Social and cultural disparities in infectious disease burden are caused by systematic differences between communities. Some differences have a direct and proportional impact on disease burden, such as health-seeking behaviour and severity of infection. Other differences-such as contact rates and susceptibility-affect the risk of transmission, where the impact on disease burden is indirect and remains unclear. Furthermore, the concomitant impact of vaccination on such inequalities is not well understood.

METHODS

To quantify the role of differences in transmission on inequalities and the subsequent impact of vaccination, we developed a novel mathematical framework that integrates a mechanistic model of disease transmission with a demographic model of social structure, calibrated to epidemiologic and empirical social contact data.

RESULTS

Our model suggests realistic differences in two key factors contributing to the rates of transmission-contact rate and susceptibility-between two social groups can lead to twice the risk of infection in the high-risk population group relative to the low-risk population group. The more isolated the high-risk group, the greater this disease inequality. Vaccination amplified this inequality further: equal vaccine uptake across the two population groups led to up to seven times the risk of infection in the high-risk group. To mitigate these inequalities, the high-risk population group would require disproportionately high vaccination uptake.

CONCLUSION

Our results suggest that differences in contact rate and susceptibility can play an important role in explaining observed inequalities in infectious diseases. Importantly, we demonstrate that, contrary to social policy intentions, promoting an equal vaccine uptake across population groups may magnify inequalities in infectious disease risk.

Public Health Consequences of a 2013 Measles Outbreak in New York City

IMPORTANCE

Internationally imported cases of measles into the United States can lead to outbreaks requiring extensive and rapid control measures. Importation of measles from an unvaccinated adolescent in 2013 led to what has been the largest outbreak of measles in New York City, New York, since 1992.

OBJECTIVE

To describe the epidemiology and public health burden in terms of resources and cost of the 2013 measles outbreak in New York City.

DESIGN, SETTING, AND PARTICIPANTS

This epidemiologic assessment and cost analysis conducted between August 15, 2013, and August 5, 2014, examined all outbreak-associated cases of measles among persons residing in New York City in 2013.

EXPOSURES

Measles virus.

MAIN OUTCOMES AND MEASURES

Numbers of measles cases and contacts. Total personnel time and total direct cost to the New York City Department of Health and Mental Hygiene (DOHMH), calculated as the sum of inputs (supplies and materials, equipment, and logistics) and personnel time (salary and fringe benefits).

RESULTS

Between March 13, 2013, and June 9, 2013, 58 persons in New York City with a median age of 3 years (range, 0-32 years) were identified as having measles. Among these individuals, 45 (78%) were at least 12 months old and were unvaccinated owing to parental refusal or intentional delay. Only 28 individuals (48%) visited a medical health care professional who suspected measles and reported the case to the DOHMH at the initial clinical suspicion. Many case patients were not immediately placed into airborne isolation, resulting in exposures in 11 health care facilities. In total, 3351 exposed contacts were identified. Total direct costs to the New York City DOHMH were $394 448, and a total of 10 054 hours were consumed responding to and controlling the outbreak.

CONCLUSIONS AND RELEVANCE

Vaccine refusals and delays appeared to have propagated a large outbreak following importation of measles into the United States. Prompt recognition of measles along with rapid implementation of airborne isolation of individuals suspected of measles infection in health care facilities and timely reporting to public health agencies may avoid large numbers of exposures. The response and containment of measles outbreaks are resource intensive.

Impact of Public Health Responses During a Measles Outbreak in an Amish Community in Ohio: Modeling the Dynamics of Transmission

We quantified measles transmissibility during a measles outbreak in Ohio in 2014 to evaluate the impact of public health responses. Case incidence and the serial interval (time between symptom onset in primary cases and secondary cases) were used to assess trends in the effective reproduction number R (the average number of secondary cases generated per case). A mathematical model was parameterized using early R values to determine the size and duration of the outbreak that would have occurred if containment measures had not been initiated, as well as the impact of vaccination. As containment started, we found a 4-fold decline in R (from approximately 4 to 1) over the course of 2 weeks and maintenance of R < 1 as control measures continued. Under a conservative scenario, the model estimated 8,472 cases (90% confidence interval (CI): 8,447, 8,489) over 195 days (90% CI: 179, 223) without control efforts and 715 cases (90% CI: 103, 1,338) over 128 days (90% CI: 117, 139) when vaccination was included; 7,757 fewer cases (90% CI: 7,130, 8,365) and 67 fewer outbreak days (90% CI: 48, 98) were attributed to vaccination. Vaccination may not account entirely for transmission reductions, suggesting that changes in community behavior (social distancing) and other control efforts (isolation, quarantining) are important. Our findings highlight the benefits of measles outbreak response and of understanding behavior change dynamics.