There are few studies that have assessed factors influencing infection control practices among health care workers (HCW) in nursing homes. We conducted a cross-sectional survey of HCWs (N = 392) in 4 nursing homes to assess whether knowledge, beliefs, and perceptions influence reported hand hygiene habits. Positive perceptions and beliefs regarding effectiveness of infection control in nursing homes were associated with reported appropriate glove use and fingernail characteristics, respectively, among HCWs. Further research on hand hygiene interventions, including targeted educational in-services should be conducted in the nursing home setting.
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.
Vaccination has reduced the global incidence of measles to the lowest rates in history. Local interruption of measles transmission, however, 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, however, does not easily translate into required immunity levels across all age groups that would be sufficient 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 is to determine age-specific immunity levels that would ensure elimination of measles using observed contact patterns from a broad range of settings. We combined recent observations on age-specific mixing patterns with scenarios for the distribution of immunity to estimate transmission potential. We validated these models by deriving predictions based on serological studies and comparing them to observed case data. We found that 95% immunity needs to be achieved at the time of school entry to guarantee elimination. The level of immunity found in * Corresponding author
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