Feasibility assessment of measles and rubella eradication.

This report addresses the epidemiological aspects and feasibility of measles and rubella eradication and the potential resource requirements in response to the request of the Director-General at the Seventieth World Health Assembly held on May 31, 2017. A guiding principle is that the path toward measles and rubella eradication should serve to strengthen primary health care, promote universal health coverage, and be a pathfinder for new vision and strategy for immunization over the next decade as laid out in the Immunization Agenda 2030. Specifically, this report: 1) highlights the importance of measles and rubella as global health priorities; 2) reviews the current global measles and rubella situation; 3) summarizes prior assessments of the feasibility of measles and rubella eradication; 4) assesses the progress and challenges in achieving regional measles and rubella elimination; 5) assesses additional considerations for measles and rubella eradication, including the results of modelling and economic analyses; 6) assesses the implications of establishing a measles and rubella eradication goal and the process for setting an eradication target date; 7) proposes a framework for determining preconditions for setting a target date for measles and rubella eradication and how these preconditions should be understood and used; and 8) concludes with recommendations endorsed by SAGE.

Combining serological and contact data to derive target immunity levels for achieving and maintaining measles elimination.

BACKGROUND: Vaccination has reduced the global incidence of measles to the lowest rates in history. However, local interruption of measles virus transmission requires sustained high levels of population immunity that can be challenging to achieve and maintain. The herd immunity threshold for measles is typically stipulated at 90-95%. This figure does not easily translate into age-specific immunity levels required to interrupt transmission. Previous estimates of such levels were based on speculative contact patterns based on historical data from high-income countries. The aim of this study was to determine age-specific immunity levels that would ensure elimination of measles when taking into account empirically observed contact patterns. METHODS: We combined estimated immunity levels from serological data in 17 countries with studies of age-specific mixing patterns to derive contact-adjusted immunity levels. We then compared these to case data from the 10 years following the seroprevalence studies to establish a contact-adjusted immunity threshold for elimination. We lastly combined a range of hypothetical immunity profiles with contact data from a wide range of socioeconomic and demographic settings to determine whether they would be sufficient for elimination. RESULTS: We found that contact-adjusted immunity levels were able to predict whether countries would experience outbreaks in the decade following the serological studies in about 70% of countries. The corresponding threshold level of contact-adjusted immunity was found to be 93%, corresponding to an average basic reproduction number of approximately 14. Testing different scenarios of immunity with this threshold level using contact studies from around the world, we found that 95% immunity would have to be achieved by the age of five and maintained across older age groups to guarantee elimination. This reflects a greater level of immunity required in 5-9-year-olds than established previously. CONCLUSIONS: The immunity levels we found necessary for measles elimination are higher than previous guidance. The importance of achieving high immunity levels in 5-9-year-olds presents both a challenge and an opportunity. While such high levels can be difficult to achieve, school entry provides an opportunity to ensure sufficient vaccination coverage. Combined with observations of contact patterns, further national and sub-national serological studies could serve to highlight key gaps in immunity that need to be filled in order to achieve national and regional measles elimination.

Forewarning of poliovirus outbreaks in the Horn of Africa: an assessment of acute flaccid paralysis surveillance and routine immunization systems in Kenya.

BACKGROUND: Although the Horn of Africa region has successfully eliminated endemic poliovirus circulation, it remains at risk for reintroduction. International partners assisted Kenya in identifying gaps in the polio surveillance and routine immunization programs, and provided recommendations for improved surveillance and routine immunization during the health system decentralization process. METHODS: Structured questionnaires collected information about acute flaccid paralysis (AFP) surveillance resources, training, data monitoring, and supervision at provincial, district, and health facility levels. The routine immunization program information collected included questions about vaccine and resource availability, cold chain, logistics, health-care services and access, outreach coverage data, microplanning, and management and monitoring of AFP surveillance. RESULTS: Although AFP surveillance met national performance standards, widespread deficiencies and limited resources were observed and reported at all levels. Deficiencies were related to provider knowledge, funding, training, and supervision, and were particularly evident at the health facility level. CONCLUSIONS: Gap analysis assists in maximizing resources and capacity building in countries where surveillance and routine immunization lag behind other health priorities. Limited resources for surveillance and routine immunization systems in the region indicate a risk for additional outbreaks of wild poliovirus and other vaccine-preventable illnesses. Monitoring and evaluation of program strengthening activities are needed.

Coverage of newborn and adult male circumcision varies among public and private US payers despite health benefits.

Studies have shown that male circumcision greatly reduces the risk for heterosexual transmission of HIV, other sexually transmitted infections, infant urinary tract infections, penile cancer, and other adverse health outcomes. Given recent data regarding these health benefits and the cost-effectiveness of newborn male circumcision, national policy makers are developing new recommendations regarding circumcision for newborn, adolescent, and adult males. To investigate the implications, this study assessed insurance coverage and reimbursement for routine newborn and adult male circumcision in private and public health plans in 2009. We found that coverage varies across private and public payers. Private insurance provides far broader coverage than state Medicaid programs for routine newborn male circumcision. Specifically, Medicaid programs in seventeen states do not cover it, even though low-income populations have a higher risk of HIV and other sexually transmitted diseases compared to higher-income groups. For adult male circumcision, coverage is generally sparse across public and private plans. Presentation of evidence-based recommendations--for example, from the Centers for Disease Control and Prevention--may be necessary if coverage for newborn and adult male circumcision is to be expanded.

New combined tetanus-diptheria-acellular pertussis vaccines for adults: primary care physician attitudes and preferences.

Availability of combined tetanus-diphtheria-acellular pertussis (Tdap) vaccines for adults offers a new pertussis prevention strategy for the US. Successful uptake of Tdap vaccine will depend partly on the attitudes and practices of primary care physicians, including their experience with Td boosters. We conducted a mail survey in August 2005 of a national random sample of 399 family physicians (FPs) and 399 general internists (IMs) to assess practices related to Td boosters, clinical experience with pertussis, and attitudes toward a potential Tdap vaccine recommendation for adults. The response rate was 49% (52% FPs, 46% IMs). Among 336 eligible respondents, half reported having clinical experience with pertussis. Most (81%) would recommend Tdap vaccine for their adult patients, and 73% support targeting adults likely to come in close contact with infants. Attitudes toward a potential Tdap vaccine recommendation differed by whether providers stock and administer Td boosters. We conclude that adult primary care providers in the US are likely to recommend Tdap vaccine to their adult patients, in concordance with recent national recommendations. Future research should assess the extent to which barriers impede adoption of Tdap vaccine recommendations.

Cost effectiveness of pertussis vaccination in adults.

BACKGROUND: Prior economic analyses have reached disparate conclusions about whether vaccinating adults against pertussis would be cost effective. Newly available data on pertussis incidence were used to evaluate the cost effectiveness of one-time adult vaccination and adult vaccination with decennial boosters. METHODS: A Markov model was used to calculate the health benefits, risks, costs, and cost effectiveness of the following strategies: (1) no adult pertussis vaccination, (2) one-time adult vaccination at 20-64 years, and (3) adult vaccination with decennial boosters. The impact of the severity of pertussis illness, vaccine adverse events, and herd immunity on model outcomes were also examined. RESULTS: At a disease incidence of 360 per 100,000, the one-time adult vaccination strategy would prevent 2.8 million cases, and the decennial vaccination strategy would prevent 8.3 million cases. As disease incidence varied from 10 to 500 per 100,000, the one-time adult vaccination strategy was projected to prevent 79,000 to 3.8 million adult pertussis cases, while the decennial vaccination program would prevent 239,000 to 11.4 million cases. A one-time adult vaccination strategy would result in 106 million people vaccinated, or approximately 64% of the adult cohort, for a total program cost of $2.1 billion, while a decennial vaccination strategy would cost $6.7 billion. The one-time and decennial booster vaccination strategies result in cost-effectiveness ratios of <$50,000 per quality-adjusted life year saved if disease incidence in adults were greater than 120 cases per 100,000 population. CONCLUSIONS: Routine vaccination of adults aged 20 to 64 years with combined tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis is cost effective if pertussis incidence in this age group is greater than 120 per 100,000 population.