The politics of immunization in public health

Human rabies post exposure prophylaxis at the Pasteur Institute of Dakar, Senegal: trends and risk factors

BACKGROUND

Rabies remains a major public health problem in developing countries. Most fatal rabies cases, especially in children, result from dog bites and occur in low-income countries, such as those in Sub-Saharan Africa. Rabies can be controlled through mass dog vaccination and human deaths prevented through timely and appropriate post-exposure prophylaxis (PEP). As access to appropriate PEP remains a serious challenge for bite-victims, the aim of this study was to understand the use of PEP, to evaluate the knowledge, attitudes and practices with respect to rabies and to identify risk factors related to non-compliance with PEP to define recommendations for improving PEP in Senegal.

METHODS

This study included patients with suspicion of rabies exposure who sought PEP at the Pasteur Institute of Dakar from April 2013 to March 2014. Patients with rabies clinical symptoms, those who had already started PEP and those with exposure outside Senegal or for more than 3 months were excluded. Data on risk factors and propensity to seek and complete PEP were collected using questionnaires and phone interviews. The association between acceptability and compliance with PEP and other independent variables were evaluated using multivariate regression analysis.

RESULTS

Among the 905 patients enrolled into the study, 67% were male (sex ratio M/F, 2) and 46%, children under 15 years of age. Exposures by animal bites represented 87%, whereas the remainder were due to scratches or contact; 76% were classified as WHO category III and 88% were due to dogs. Among these patients, 7% refused to start PEP and 54.5% completed the full schedule. Main factors reported by non-compliant patients were vaccine costs and affordability, and knowledge on status of biting animal.

CONCLUSION

This study shows that despite the awareness about rabies dangers and prevention, only half of the patients completed the full PEP schedule. The following recommendations, such as free of charge prophylaxis or intradermal regimens as an alternative to intramuscular regimens, should be considered to increase the adherence to PEP at the Pasteur Institute of Dakar and in Senegal.

Human and animal rabies prevention and control cost in Bhutan, 2001-2008: the cost-benefit of dog rabies elimination

The objective of this study was to estimate the cost of various interventions and to quantify the economic impacts of rabies in Bhutan. Cost-benefit of dog rabies elimination versus human post exposure treatment cost was also assessed. The average direct medical cost of human post-exposure treatment (using rabies vaccine only) was estimated to be Nu. 1615 (US$ 35.65) per 5-dose Essen regimen per patient. The cost would increase to Nu. 2497 (US$ 55.13) and Nu. 19,633 (US$ 433.41) per patient when one dose of either equine rabies immunoglobulin (ERIG) or human rabies immunoglobulin (HRIG) is administered, respectively. The societal cost (direct medical and indirect patient expenses) per patient was estimated to be Nu. 2019 (US$ 45), Nu. 2901 (US$ 64) and Nu. 20,037 (US$ 442) using vaccine only, vaccine with ERIG and vaccine with HRIG, respectively. The average cost per dog vaccination and sterilization were estimated to be Nu. 75 (US$ 1.66) and Nu. 288 (US$ 6.36), respectively. The total direct cost of rabies and various interventions between 2001 and 2008 was estimated to be Nu. 46.95 million (US$ 1.03 million). The direct cost for intensified human PET was estimated to be Nu. 5.85 million (US$ 0.11 million) per year with a cumulated estimated costs of Nu. 35.10 million (US$ 0.70 million) while the cost of mass dog vaccination with at least 70% coverage is estimated to be approximately Nu. 10.31 million (US$ 0.21 million) at the end of 6 years. The combined cost of mass dog vaccination and human PET was estimated to be greater than the cost of human PET alone during the first 2 years of the campaign, and then would be lower than human PET cost alone after the 5th year of the campaign. The total cumulated cost of the combined strategy was estimated to be Nu. 34.14 million (US$ 0.73 million) and would be lower than the cumulated cost of human PET alone (Nu. 35.10 million, US$ 0.77 million) at the end of 6 years. Rabies represents a substantial economic impact to the Bhutanese society. Well-planned and implemented mass dog vaccination would result in elimination of rabies reservoirs in the domestic dog population and would eliminate human rabies cases. It would also reduce the recurrent expenditure on human post-exposure treatment.

Human rabies post exposure prophylaxis in Bhutan, 2005-2008: trends and risk factors

The aim of this study was to understand the use and distribution of human rabies post exposure prophylaxis (PEP) vaccine in Bhutan and to identify risk factors for receiving an incomplete course of the vaccine. We analyzed post exposure treatment records from 28 medical hospitals from 2005 to 2008. Males (59%) accounted for significantly more PEP events than females (41%) across all age groups (P<0.001). Children - particularly 5-9 years of age - received more rabies PEP than other age groups. Animal bite and non-bite accounted for 27% (n=2239) and 16% (n=1303) of rabies PEP, respectively, whilst 57% (n=4773) of the PEP events had no recorded information about the reasons for post exposure treatment. Post exposure treatment was provided throughout the year with a higher number during the winter and spring months. The number of PEP events significantly (P<0.001) increased between 2005 and 2008, from <1000 to >2800 events, respectively. Significantly (P<0.001) more PEP events were reported from the southern parts of Bhutan that are endemic for rabies or those areas in eastern Bhutan that have reported rabies outbreaks than other parts of Bhutan. Forty percent (n=3360) of the patients received an incomplete course of vaccine (<5-doses of vaccine intramuscular). Results suggest that patients with animal bite injury were less likely to receive an incomplete vaccine course than non-bite recipients, and patients presented to hospitals in rabies endemic or outbreak areas were less likely to receive an incomplete course than in non-rabies areas or rabies free areas. Similarly, patients presenting to hospitals for PEP during spring and summers months were less likely to receive an incomplete vaccine course than those during other seasons. Public education campaigns need to be conducted in Bhutan to reduce dog bite incidents and also to prevent mass exposures to rabies. A thorough assessment of each individual case based on the WHO guidelines would reduce unnecessary PEP (and therefore costs) in Bhutan.

Rabies postexposure prophylaxis, New York, 1995-2000

Bats are now the leading source of rabies postexposure prophylaxis.

The epidemiology of human rabies postexposure prophylaxis (PEP) in 4 upstate New York counties was described from data obtained from 2,216 incidences of PEP recorded by local health departments from 1995 to 2000. Overall annual incidence for the study period was 27 cases per 100,000 persons. Mean annual PEP incidence rates were highest in rural counties and during the summer months. PEP incidence was highest among patients 5–9 and 30–34 years of age. Bites accounted for most PEP (51%) and were primarily associated with cats and dogs. Bats accounted for 30% of exposures, more than any other group of animals; consequently, bats have replaced raccoons as the leading rabies exposure source to humans in this area.

A decision-analytic approach to postexposure rabies prophylaxis

The risks and benefits of postexposure rabies prophylaxis were analyzed from clinical and economic perspectives. A decision-analytic model was constructed by using probability and outcome data from the literature and the state health department. Health outcomes were measured in quality-adjusted life years. In the base case (overweight adult male), treatment is optimal when the probability of animal rabidity is greater than 1 in 2000. Sensitivity analysis showed robustness in the treatment decision; however, the incremental cost-effectiveness ratio ($140,000/quality-adjusted life year) is sensitive to the rabidity probability. Treatment is optimal from the patient's perspective; however, it may not be cost-effective when the probability of rabidity is low.