Side-by-side Comparative Study of the Immunogenicity of the Intramuscular and Intradermal Rabies Post-exposure Prophylaxis Regimens in a Cohort of Suspected Rabies Virus Exposed Individuals.

All World Health Organization (WHO) pre-qualified rabies vaccines for humans are inactivated tissue culture rabies virus formulations produced for intramuscular (IM) administration. Due to costs and vaccine shortage, dose-saving intradermal (ID) administration of rabies post-exposure prophylaxis (PEP) is encouraged by WHO. This study compared the immunogenicity of the ID 2-site, 3-visit Institut Pasteur Cambodge (IPC) PEP regimen to the IM 1-site, 4-visit 4-dose Essen regimen using Verorab vaccine (Sanofi). The development of neutralizing antibodies (nAbs) and T cell response was assessed in 210 patients with a category II or III animal exposure in a rabies-endemic country. At day 28, all participants developed nAbs (≥0.5 IU/mL), irrespective of PEP scheme, age, or administration of rabies immunoglobulin. T cell response and nAb titers were similar for both PEP schemes. This study demonstrated that the 1-week ID IPC regimen is as effective as the 2-week IM 4-dose Essen regimen in inducing an anti-rabies immune response under real-life PEP.

Impact of the switch from four to three intradermal rabies post-exposure prophylaxis sessions in patients bitten by dogs: A cost-consequence analysis from the patients' perspective.

The annual incidence of rabies deaths has been estimated in Cambodia at nearly 5.8/100,000 person-years. The cost of post exposure prophylaxis (PEP) and travel is potentially a significant barrier for exposed patients and their families, although safety nets are in place to provide the prophylaxis at no cost for low-income families. A decision-tree model was built to estimate changes in the costs from the patients' perspective and the survival outcomes of the Institut Pasteur du Cambodge (IPC) rabies PEP regimen after the switch from the Thai Red Cross (TRC) rabies PEP regimen in patients exposed to WHO category II or III bites by dogs. Derived from the IPC database, data included the trajectory of 203,497 patients, 1412 called-back patients and economic data on 201 patients. Uncertainty was addressed using one-way and probabilistic sensitivity analyses. Compared to the TRC regimen, the IPC regimen was cheaper and equally effective in patients with category II bites. In patients with category III bites, the IPC regimen was cheaper and its modeled probability of survival was 0.04% (95% CI, -0.12%; 0%) lower than the TRC regimen. However, the mortality rate was very low and the causes of death were uncertain. The data available may have lacked power to be able to statistically significantly tell apart the difference between genuine PEP failure and incorrect PEP administration, in the three versus the four-PEP sessions.

A 1-week intradermal dose-sparing regimen for rabies post-exposure prophylaxis (RESIST-2): an observational cohort study.

BACKGROUND: The international health authorities are backing an effort to eliminate canine-mediated rabies in humans by 2030. This effort will require improving access to adequate and timely rabies post-exposure prophylaxis as compliance is low with WHO-recommended regimens (given in four to five visits over 1 month). Access could be substantially improved by an abridged regimen to reduce doses, direct and indirect costs, and improve vaccine equity by better sharing of available vaccine. We aimed to compare rabies virus neutralising antibody titres before and after the fourth visit to determine whether that session was needed or the current regimen could be abridged. METHODS: In this observational cohort study, we measured rabies virus neutralising antibody titres using rapid fluorescent focus inhibition tests in 116 people bitten by dogs with laboratory-confirmed rabies and 20 control individuals. Percentages of circulating plasmablasts were determined by flow cytometry. All individuals had been referred to the rabies prevention clinic at Institut Pasteur in Cambodia and received two intradermal injections of post-exposure prophylaxis on days 0, 3, 7, and 28 (Thai Red Cross regimen) with or without equine rabies immunoglobulin, as per 2010 WHO recommendations. FINDINGS: All individuals had rabies virus neutralising antibody titres considered protective (≥0·5 IU/mL) and plasmablast activation on day 28 before the last injection. The median rabies virus neutralising antibody concentration in the group of individuals bitten by rabies virus-positive dogs was 1·08 IU/mL (IQR 0·37-3·09) on day 7, 26·86 (22·68-49·50) on day 28, and 26·74 (11·78-49·06) on day 42. No significant differences were observed in titres between days 28 and 42, after titres reached a plateau. These titres were reached notwithstanding equine rabies immunoglobulin use, age, sex, nutrition status as indicated by upper-arm circumference in children or BMI in adults, or dog infection status. Titres or plasmablast percentages did not increase between the day of the last injection and 2 weeks later. All patients were alive 1 year after post-exposure prophylaxis. INTERPRETATION: The fourth vaccine session on day 28 provides no additional benefit. Rabies post-exposure prophylaxis can be abridged to a two-dose, three-session, 1 week regimen to improve post-exposure prophylaxis coverage and equity at no risk to patients. FUNDING: Institut Pasteur.

Intradermal rabies post-exposure prophylaxis can be abridged with no measurable impact on clinical outcome in Cambodia, 2003-2014.

Rabies causes 60,000 deaths worldwide annually. Rabies post-exposure prophylaxis is highly effective but often geographically and financially beyond reach in endemic developing countries. We conducted a retrospective study on clinical outcome at ≥6 months in 3318 Cambodians who received intradermal Vero cell vaccine post-exposure prophylaxis after a bite by a rabid or sick-looking but untested dog in 2003-2014. An external expert panel examined verbal autopsy reports to identify rabies deaths. 1739 (93.65%) persons bitten by rabid- and 1066 (72.96%) bitten by sick-looking but untested dogs were traced and 513 were lost to follow-up. Among the former, 1591 (91.49%) and 129 (7.42%) patients referred for 4+ and 3 post-exposure prophylaxis sessions, respectively. Three persons died of probable rabies so that the overall percentage of survival was 99.83% (95% exact confidence interval: 99.49-99.96%) in post-exposure prophylaxis recipients bitten by confirmed rabid dogs. No significant difference was found in survival among patients who received 3 vs. 4+ sessions (with or without rabies immunoglobin). The power of the study, however, was limited. The current four sessions/one month intradermal regimen can be reduced to a three sessions/one week at no detectable added risk to patients, with the limitation of study power at 49%. A clinical follow-up system should be adopted by rabies prevention centers, especially to monitor implementation of an abridged course. The Institut Pasteur in Cambodia regimen will improve vaccine equity by treating 33% more patients with available doses, reduce direct cost of vaccination, transportation and other indirect costs to vaccinees.

Rabies Postexposure Prophylaxis Noncompletion After Dog Bites: Estimating the Unseen to Meet the Needs of the Underserved.

Postexposure prophylaxis (PEP) prevents human rabies and is accessible in Cambodia principally in Phnom Penh, the capital. Timely, affordable access to PEP is a challenge for the mainly rural population. We aimed to identify districts independently associated with PEP noncompletion to position frontline vaccination centers. We analyzed the 2009-2013 database at the Rabies Prevention Center at the Institut Pasteur du Cambodge, Phnom Penh. Logistic regressions identified nongeographic determinants of PEP noncompletion as well as the districts that were independently associated with noncompletion after adjustment for these determinants. The influence of distance by road was estimated using a boosted regression-trees model. We computed a population attributable fraction (rabies index (RI)) for each district and developed a map of this RI distribution. A cartographic analysis based on the statistic developed by Getis and Ord identified clusters of high-RI districts. Factors independently associated with noncompletion were patients' district of residence, male sex, age 15-49 years, initial visit during rice harvest, the dog's status (culled or disappeared), and a prescribed PEP protocol requiring more than 3 PEP sessions (4 or 5). Four clusters of high-RI districts were identified using this analytical strategy, which is applicable to many vaccination or other health services. Positioning frontline PEP centers in these districts could significantly widen access to timely and adequate PEP.

Caring for patients with rabies in developing countries - the neglected importance of palliative care.

Although limited publications address clinical management of symptomatic patients with rabies in intensive care units, the overwhelming majority of human rabies cases occur in the rural setting of developing countries where healthcare workers are few, lack training and drugs. Based on our experience, we suggest how clinicians in resource-limited settings can make best use of essential drugs to provide assistance to patients with rabies and their families, at no risk to themselves. Comprehensive and compassionate patient management of furious rabies should aim to alleviate thirst, anxiety and epileptic fits using infusions, diazepam or midazolam and antipyretic drugs via intravenous or intrarectal routes. Although the patient is dying, respiratory failure must be avoided especially if the family, after being informed, wish to take the patient home alive for funereal rites to be observed. Healthcare staff should be trained and clinical guidelines should be updated to include palliative care for rabies in endemic countries.

Necrotic Tuberculin Skin (Mantoux) Test Reaction: A Case Report and an Estimation of Frequency.

Tuberculin skin testing was performed on a 5-year-old girl in Phnom Penh, Cambodia. She had been immunized by Bacille de Calmette et Guérin. She was tested because of a palpable cervical node and a slightly elevated temperature. Within 48 h, a deep necrotic lesion appeared on the volar aspect of the left arm. The lesion was treated locally, and the child was not treated for suspected TB. To our knowledge, this is the first instance of necrosis in 11,392 people who received Tubersol doses since 1996 to date at our International Vaccination Center, for an estimated incidence of 0.18 per 1,000 (95% Poisson 0.04-0.70 per 1,000 doses used). At a follow-up consultation after 77 days, the lesion had scarred and the child showed no signs suggestive of active TB. Although latent TB infection remains the most likely diagnosis, other types of mycobacterial infection may be considered in the tropical setting and in the absence of signs suggestive of active TB.

Rabies Vaccine and Rabies Immunoglobulin in Cambodia: Use and Obstacles to Use.

BACKGROUND: Authorities have pledged to eliminate canine rabies by 2020 in Cambodia, a country with a very high rabies burden. Logistic and financial access to timely and adequate postexposure prophylaxis (PEP) is essential for preventing rabies in humans. METHODS: We undertook a survey of the few identified sites where PEP rabies vaccination and rabies immunoglobulin (RIG) are available in Cambodia. We examined the Rabies Prevention Center at Institut Pasteur du Cambodge (rpc@ipc) database and rpc@ipc order forms for 2012 to assess vaccine and RIG use. We conducted a rapid internet survey of centers that provide rabies vaccine and RIG in Cambodia, other than rpc@ipc. RESULTS: The cost of a full course of intramuscular or intradermal PEP in Cambodia, with and without RIG, was also estimated. Rabies vaccination is free of charge in one foundation hospital and is accessible for a fee at Institut Pasteur du Cambodge (IPC), some institutions, and some Cambodian private clinics. In 2012, 27,500 rabies vaccine doses (0.5 mL) and 591 equine RIG doses were used to provide intradermal PEP to 20,610 persons at rpc@ipc following animal bites. Outside of rpc@ipc, an estimated total of 53,400 vaccine doses and 200 RIG doses were used in Cambodia in 2012. The wholesale cost of full rabies PEP was estimated at 50% to 100% of a Cambodian farmer's monthly wage. CONCLUSIONS: Local populations and travelers cannot be sure to locally access adequate and timely PEP due to high costs and low access to RIG. Travelers to high-endemic areas such as Cambodia are strongly encouraged to undergo pre-exposure vaccination or seek expert advice, as per World Health Organization (WHO) recommendations. State-subsidized, pre-positioned stocks of human vaccine and RIG in bite management centers would extend the rabies prevention centers network. Support from Institut Pasteur du Cambodge for staff training, cold chain, and quality control would contribute to reducing the risk of rabies deaths in Cambodia.