Simplification of Rabies Postexposure Prophylaxis: A New 2-Visit Intradermal Vaccine Regimen.

A 2-visit multiple-site intradermal (ID) vaccine protocol would be the most economical, immunogenic, and practicable regimen for postexposure rabies prophylaxis (PEP) in clinics seeing few patients a month. This regimen with an additional day 28 dose is now recommended by the WHO. The difficulties surrounding ID rabies vaccination have hindered progress in provision of prophylaxis, especially in rural Asia and Africa. Although the latest WHO recommendations include 1-week ID postexposure vaccine regimens, these are unlikely to prove economical where rabies vaccination is presently unavailable. The new protocol uses a whole vial of vaccine divided between 4-sites ID on the first day and half a vial at 2-sites ID on day 7. Gavi has recently approved support for rabies PEP. This 2-visit 4-site ID regimen, with or without a day 28 dose, should be considered for implementation in this remarkable new initiative.

The Imperative of Palliation in the Management of Rabies Encephalomyelitis.

The aim of this review is to guide clinicians in the practical management of patients suffering from rabies encephalomyelitis. This condition is eminently preventable by modern post-exposure vaccination, but is virtually always fatal in unvaccinated people. In the absence of any proven effective antiviral or other treatment, palliative care is an imperative to minimise suffering. Suspicion of rabies encephalomyelitis depends on recognising the classic symptomatology and eliciting a history of exposure to a possibly rabid mammal. Potentially treatable differential diagnoses must be eliminated, notably other infective encephalopathies. Laboratory confirmation of suspected rabies is not usually possible in many endemic areas, but is essential for public health surveillance. In a disease as agonising and terrifying as rabies encephalomyelitis, alleviation of distressing symptoms is the primary concern and overriding responsibility of medical staff. Calm, quiet conditions should be created, allowing relatives to communicate with the dying patient in safety and privacy. Palliative management must address thirst and dehydration, fever, anxiety, fear, restlessness, agitation, seizures, hypersecretion, and pain. As the infection progresses, coma and respiratory, cardiovascular, neurological, endocrine, or gastrointestinal complications will eventually ensue. When the facilities exist, the possibility of intensive care may arise, but although some patients may survive, they will be left with severe neurological sequelae. Recovery from rabies is extremely rare, and heroic measures with intensive care should be considered only in patients who have been previously vaccinated, develop rabies antibody within the first week of illness, or were infected by an American bat rabies virus. However, in most cases, clinicians must have the courage to offer compassionate palliation whenever the diagnosis of rabies encephalomyelitis is inescapable.

Rabies: the clinical features, management and prevention of the classic zoonosis.

The diagnosis of rabies encephalitis relies on awareness of the varied clinical features and eliciting a history of unusual contact with a mammal throughout the endemic area. The diagnosis is easily missed. Laboratory tests are not routine and only confirm clinical suspicion. Rabies infection carries a case fatality exceeding 99.9%. Palliation is appropriate, except for previously-vaccinated patients or those infected by American bats, for whom intensive care is probably indicated. However, as rabies vaccines are outstandingly effective, no one should die of dog-transmitted infection. Vaccines and rabies immunoglobulin are expensive and usually scarce in Asia and Africa. All travellers to dog rabies enzootic areas should be strongly encouraged to have pre-exposure immunisation before departure. There is no contraindication to vaccination but the cost can be prohibitive. Intradermal immunisation, using 0.1 ml and sharing vials of vaccine, is cheaper and is now permitted by UK regulations. Returning travellers may need post-exposure prophylaxis. Economical intradermal post-exposure vaccination is practicable and should be introduced into rural areas of Africa and Asia immediately. Eliminating rabies in dogs is now feasible and would dramatically reduce human mortality, if funds were made available. The high current economic burden of human prophylaxis would then be largely relieved.

Management of rabies in humans.

Rabies is a fatal disease in humans, and, to date, the only survivors of the disease have received rabies vaccine before the onset of illness. The approach to management of the rabies normally should be palliative. In unusual circumstances, a decision may be made to use an aggressive approach to therapy for patients who present at an early stage of clinical disease. No single therapeutic agent is likely to be effective, but a combination of specific therapies could be considered, including rabies vaccine, rabies immunoglobulin, monoclonal antibodies, ribavirin, interferon-alpha, and ketamine. Corticosteroids should not be used. As research advances, new agents may become available in the future for the treatment of human rabies.

Deaths from symptomatically identifiable furious rabies in India: a nationally representative mortality survey.

BACKGROUND: It is estimated that India has more deaths from rabies than any other country. However, existing estimates are indirect and rely on non-representative studies. METHODS AND PRINCIPAL FINDINGS: We examined rabies deaths in the ongoing Million Death Study (MDS), a representative survey of over 122,000 deaths in India that uses enhanced types of verbal autopsy. We estimated the age-specific mortality rates of symptomatically identifiable furious rabies and its geographic and demographic distributions. A total of 140 deaths in our sample were caused by rabies, suggesting that in 2005 there were 12,700 (99% CI 10,000 to 15,500) symptomatically identifiable furious rabies deaths in India. Most rabies deaths were in males (62%), in rural areas (91%), and in children below the age of 15 years (50%). The overall rabies mortality rate was 1.1 deaths per 100,000 population (99%CI 0.9 to 1.4). One third of the national rabies deaths were found in Uttar Pradesh (4,300) and nearly three quarters (8,900) were in 7 central and south-eastern states: Chhattisgarh, Uttar Pradesh, Odisha, Andhra Pradesh, Bihar, Assam, and Madhya Pradesh. CONCLUSIONS AND SIGNIFICANCE: Rabies remains an avoidable cause of death in India. As verbal autopsy is not likely to identify atypical or paralytic forms of rabies, our figure of 12,700 deaths due to classic and clinically identifiable furious rabies underestimates the total number of deaths due to this virus. The concentrated geographic distribution of rabies in India suggests that a significant reduction in the number of deaths or potentially even elimination of rabies deaths is possible.

Rabies and African bat lyssavirus encephalitis and its prevention.

Unlike any other human infection, encephalitis caused by dog rabies virus is always fatal. Rabies and other lyssaviruses have been found in unexpected places, and human disease, especially paralytic rabies, has gone unrecognised. Evidence is emerging that rabies-related bat lyssaviruses are enzootic across Europe, Africa, Asia and Australia, but none has been detected in the Americas. The epidemiology and origins of African lyssaviruses are discussed. Ideal rabies prophylaxis (pre-exposure immunisation followed by post-exposure booster vaccination) has proved 100% effective; hence all human deaths result from failure of prevention. Rabies vaccines of known quality are unaffordable for the majority in Africa. Although intradermal regimens requiring <40% of the usual vaccine dose are economical and are recommended by the World Health Organization, several problems have inhibited their use. A new, simplified, economical post-exposure vaccine regimen that uses an initial dose of intradermal injections at four sites overcomes many of the difficulties of the previous methods: it is at least as immunogenic as the standard intramuscular course of tissue-culture vaccine; is safer in inexperienced hands; requires fewer than two ampoules of vaccine and only three instead of five clinic visits. Recent data should increase the confidence of physicians to use the World Health Organization-accredited rabies vaccines more efficiently and at lower cost.

Emerging aspects of rabies infection: with a special emphasis on children.

PURPOSE OF REVIEW: Increased awareness of the long-neglected rabies virus could promote the highly effective methods of preventing human deaths. Rabies and rabies-related lyssaviruses have recently been appearing in unexpected places, sometimes with dire consequences. Although rabies of canine origin remains 100% fatal in human beings, should the surprising recovery of a single unvaccinated child influence treatment now? RECENT FINDINGS: Evidence of rabies-related lyssavirus infection of bats is increasing across continents and with new virus types. Human rabies has been misdiagnosed as cerebral malaria, or even drug abuse. Organ transplant recipients have been infected. The first unvaccinated patient, a teenager, bitten by a bat, recovered from rabies encephalitis, but why might this be? Highly effective control and prevention of infection is possible. Preexposure prophylaxis for schoolchildren could now become routine. Improved economical intradermal postexposure vaccine regimens could increase the availability of affordable treatment in developing countries. Controlling dog rabies could prevent 95% of human deaths, but education and resources are lacking. SUMMARY: The risks and problems of rabies and other lyssaviruses vary greatly across the world. Knowledge of epidemiology and prevention could save the lives of victims of animal bites and promote efforts to control and even eliminate dog rabies.

A simplified 4-site economical intradermal post-exposure rabies vaccine regimen: a randomised controlled comparison with standard methods.

BACKGROUND: The need for economical rabies post-exposure prophylaxis (PEP) is increasing in developing countries. Implementation of the two currently approved economical intradermal (ID) vaccine regimens is restricted due to confusion over different vaccines, regimens and dosages, lack of confidence in intradermal technique, and pharmaceutical regulations. We therefore compared a simplified 4-site economical PEP regimen with standard methods. METHODS: Two hundred and fifty-four volunteers were randomly allocated to a single blind controlled trial. Each received purified vero cell rabies vaccine by one of four PEP regimens: the currently accepted 2-site ID; the 8-site regimen using 0.05 ml per ID site; a new 4-site ID regimen (on day 0, approximately 0.1 ml at 4 ID sites, using the whole 0.5 ml ampoule of vaccine; on day 7, 0.1 ml ID at 2 sites and at one site on days 28 and 90); or the standard 5-dose intramuscular regimen. All ID regimens required the same total amount of vaccine, 60% less than the intramuscular method. Neutralising antibody responses were measured five times over a year in 229 people, for whom complete data were available. FINDINGS: All ID regimens showed similar immunogenicity. The intramuscular regimen gave the lowest geometric mean antibody titres. Using the rapid fluorescent focus inhibition test, some sera had unexpectedly high antibody levels that were not attributable to previous vaccination. The results were confirmed using the fluorescent antibody virus neutralisation method. CONCLUSIONS: This 4-site PEP regimen proved as immunogenic as current regimens, and has the advantages of requiring fewer clinic visits, being more practicable, and having a wider margin of safety, especially in inexperienced hands, than the 2-site regimen. It is more convenient than the 8-site method, and can be used economically with vaccines formulated in 1.0 or 0.5 ml ampoules. The 4-site regimen now meets all requirements of immunogenicity for PEP and can be introduced without further studies. TRIAL REGISTRATION: Controlled-Trials.com ISRCTN 30087513.

The challenge to provide affordable rabies post-exposure treatment.

Treatment with Semple or suckling mouse brain rabies vaccines persists in many countries of Asia, Africa and South America. Its replacement depends on the immediate accessibility of effective affordable alternative treatment with tissue culture vaccines (TCVs). The use of the expensive European TCVs has been possible in Asia by means of economical intradermal (ID) post-exposure vaccine regimens. Implementation of this effective economical treatment has been delayed by the complexity and inconvenience of the regimens, and the reluctance to change prophylaxis against a fatal disease. Up to now, the ID regimens have been used only where passive immunisation with rabies immune globulin (RIG) is usually available. Rabies deaths despite optimal vaccine treatment have been attributed to lack of RIG. The ID regimens might soon be promoted in areas where RIG is not even available for severe exposure. It is therefore vital that economical vaccine regimens should be used which induce protective immunity rapidly. Improvements in rabies pet in developing countries could be made by: (i). publicising the urgency and efficacy of wound cleaning; (ii). facilitating the replacement of nervous tissue vaccines by economical ID treatment with TCVs; (iii). using an ID regimen with a large dose of vaccine on the first day of treatment especially when no RIG is available; and (iv). promoting pre-exposure prophylaxis to eliminate the need for RIG and provide better rabies prophylaxis.