On the path to rabies elimination: The need for risk assessments to improve administration of post-exposure prophylaxis

Abstract

Background: Costs of rabies post-exposure prophylaxis (PEP) often remain high in regions where rabies has been controlled in dogs, presenting a challenge for sustaining rabies elimination programmes. We investigated the potential for bite patient risk assessments to improve PEP provision and surveillance in settings approaching elimination of dog-mediated rabies.

Methods: We conducted a longitudinal study of patients presenting to animal bite treatment centres (ABTCs) on the island province of Bohol in the Philippines to investigate the health status of biting dogs and to quantify current expenditure on PEP.

Results: Incidence of bite patients presenting to ABTCs was high (>300/100,000 persons/year) and increasing, resulting in substantial health provider costs. Over $142,000 was spent on PEP in 2013 for a population of 1.3 million. From follow up of 3820 bite patients we found that >92% were bitten by healthy dogs (alive 14 days after the bite) and just 1.4% were bitten by probable or confirmed rabid dogs. The status of dogs that bit 6% of patients could not be determined. During the course of investigations of bites by suspect dogs, we were able to obtain samples for case confirmation, identify exposed persons who had not sought PEP as well as in-contact dogs at risk of developing rabies. We calculate that expenditure on PEP could at least be halved through more judicious approaches to provision of PEP, based on the histories of biting animals determined through risk assessments with bite patients.

Conclusions: We conclude that a One Health approach to surveillance based on Integrated Bite Case Management could improve the sustainability and effectiveness of rabies elimination programmes while also improving patient care by identifying those genuinely in need of lifesaving PEP.

Keywords: Dog-mediated rabies; Dose-sparing; Freedom from disease; IBCM; Immunoglobulin; Integrated Bite Case Management; Intradermal; Intramuscular; One Health; Post-exposure vaccination; Rabies prevention; Risk assessment; Surveillance; Verification.

Fig. 1

Bohol Province in the Central Visayas, Region VII of the Philippines, showing the human population density and locations of clinics providing PEP to bite patients. Human density was estimated at the barangay-level (village) based on the 2015 census. The inset shows the location of Bohol (blue) in the Philippines.

Fig. 2

Study protocol indicating process (A) from recording of bite victim to completion of investigation and (B) outcomes of study. Bite incidents are recorded by health workers when patients report to anti-rabies clinics. Health Workers aimed to call patients 14 days after their first clinic presentation to ascertain any changes in the biting animal's behaviour or health condition (in practice calls were made at least within 30 days of the patient presentation). In the instance of the biting animal being sick, found dead, killed or untraceable, field investigations were conducted, followed by brain sample collection where relevant and available. Under the protocols operating in the Philippines at the time of the study, PEP was continued irrespective of field investigation or the status of the biting animal. ABTC = Animal Bite Treatment Centre, ABC = Animal Bite Clinic, RHU = Rural Health Unit, MAO = Municipal Agricultural Office, GARC = Global Alliance for Rabies Control office, OPV = Office of the Provincial Veterinarian, PHO = Provincial Health Office.

Fig. 3

Annual time series of (A) bite patient incidence reporting for PEP per 100,000 and (B) human rabies cases from the beginning of rabies control programme on Bohol in 2007 until 2013.

Fig. 4

The distribution and monthly time series of dog bite patients and confirmed/probable rabies exposures receiving PEP from ABTCs and ABCs in 2013. Dog bites are shown by the line and rabies exposures are shown by the bars (bites and meat consumption shown in dark and light grey, respectively).

Fig. 5

Breakdown of patients attending ABTC/ABCs in 2013 according to their exposure status and implications for PEP expenditure. (A) Number of patients classified per WHO exposure category; (B) monthly time series of bite patients according to the status of biting animals after the 14-day observation period classified from phone call follow up and (C) estimated PEP and surveillance costs under the current and two alternative scenarios. Training of nurses in phone call follow up of patients was only completed in January 2013. Hence not all patients were followed up (phone numbers were not previously recorded routinely) in January 2013. A total of 15 field investigations were initiated following identification of suspect dogs during phone call follow up.

Fig. 6

Locations of confirmed and probable rabid animals identified during investigations. The estimated dog vaccinated coverage at the municipality level based on dog vaccinations in October 2013 is also shown.