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rabies

Key data

  • Rabies is a serious public health problem in over 150 countries and territories, mainly in Asia and Africa. It is a viral, zoonotic, neglected tropical disease that causes tens of thousands of deaths each year, 40% of which affect children under 15 years of age.
  • 99% of rabies cases in humans are caused by dog ​​bites and scratches. Vaccination and bite prophylaxis for dogs can be the cause.
  • Once the virus infects the central nervous system and clinical symptoms appear, rabies is fatal in 100% of cases.
  • However, deaths from rabies can be prevented by immediate post-exposure prophylaxis (PEP) by preventing the virus from reaching the central nervous system. PEP consists of thorough wound irrigation, administration of a human rabies vaccine, and, if indicated, rabies immunoglobulin (RIG).
  • If a person is bitten or scratched by a possibly rabid animal, they should always seek PEP treatment immediately.
  • The goal of WHO and its global partners is to end deaths from dog-transmitted rabies through a comprehensive One Health approach that includes promoting mass vaccination of dogs, ensuring access to PEP, training health workers, improving surveillance and preventing bites through community education.

overview

Rabies transmitted by dogs

Rabies is a vaccine-preventable, zoonotic viral disease that affects the central nervous system. In up to 99% of human rabies cases, dogs are responsible for transmitting the virus. Children between the ages of 5 and 14 are often victims.

Rabies infects mammals, including dogs, cats, livestock and wild animals.

Rabies is transmitted to humans and animals through saliva, usually through bites, scratches, or direct contact with mucous membranes (e.g. eyes, mouth, or open wounds). Once clinical symptoms appear, rabies is fatal in almost 100% of cases.

The global cost of rabies is estimated at around US$8.6 billion per year, including loss of life and livelihoods, medical care and related costs, and incalculable psychological trauma.

Rabies occurs on all continents except Antarctica. Worldwide, an estimated 59,000 people die of rabies each year. However, due to under-reporting, the documented number of cases often differs from the estimate.

Rabies is a neglected tropical disease (NTD) that primarily affects marginalized populations. Although effective vaccines and immunoglobulins against rabies exist, these are often inaccessible or unaffordable for those affected.

In 2018, the estimated average cost of rabies post-exposure prophylaxis (PEP) was US$108 (plus travel costs and loss of income), which can be a financial burden for people earning US$1–2 per person per day.

More than 29 million people worldwide receive a human rabies vaccine each year.

Rabies from sources other than dogs

In the Americas, where dog-borne rabies is largely under control, blood-sucking bats are now the main source of rabies in humans. Bat-borne rabies is also a growing public health threat in Australia and parts of Western Europe.

Deaths from contact with foxes, raccoons, skunks and other wild mammals are very rare. Rabies is not transmitted through rodent bites; this is not known.

Infection with rabies through inhalation of virus-containing aerosols, consumption of raw meat or milk from infected animals, or through an organ transplant is extremely rare.

Transmission from person to person through bites or saliva is theoretically possible, but has never been confirmed.

Problem Description

The incubation period for rabies is usually 2–3 months, but can vary from one week to one year depending on factors such as where the virus entered and viral load. The early symptoms of rabies include general signs such as fever, pain, and unusual or unexplained tingling, stinging, or burning at the wound site. If the virus enters the central nervous system, a progressive and fatal inflammation of the brain and spinal cord develops. Clinical rabies in humans can be controlled but very rarely cured, and not without severe neurological deficits.

There are two forms of rabies:

  • Raging Rabies leads to hyperactivity, states of excitement, hallucinations, coordination disorders, hydrophobia (fear of water) and aerophobia (fear of drafts or fresh air). Death occurs after a few days due to cardiac arrest.
  • Paralytic rabies accounts for about 20% of all human cases. This form of rabies is less dramatic and usually lasts longer than the rabid form. Muscles gradually become paralyzed, starting at the wound. A coma slowly develops and eventually death occurs. The paralytic form of rabies is often misdiagnosed, which contributes to the disease being underreported.

diagnosis

There are currently no WHO-approved diagnostic tools to detect rabies infection before the onset of clinical disease.

The clinical diagnosis of rabies is difficult without a reliable history of contact with a rabid animal or specific symptoms of hydrophobia or aerophobia.

An accurate risk assessment is crucial for the decision to administer PEP.

Once symptoms appear and death is inevitable, comprehensive and compassionate palliative care is recommended.

Postmortem confirmation of rabies infection is achieved by various diagnostic techniques that detect whole viruses, viral antigens or nucleic acids in infected tissues (brain, skin or saliva).

If possible, the biting animal should be tested.

prevention

Vaccination of dogs

Vaccination of dogs, including puppies, as part of mass vaccination programs is the most cost-effective strategy for preventing rabies in humans because it stops transmission at the source.

Culling free-roaming dogs is not an effective way to combat rabies.

consciousness

Public education about dog behavior and bite prevention, what to do if bitten or scratched by a potentially rabid animal, and responsible pet ownership are essential complements to rabies vaccination programs.

Vaccinating people

Effective vaccines are available to immunize people both before and after possible exposure. As listed in the WHO Medical Device Prequalification, as of 2024, only three WHO prequalified rabies vaccines for humans are available worldwide: RABIVAX-S from Serum Institute of India Pvt. Ltd., VaxiRab N from Zydus Lifesciences Limited and VERORAB from Sanofi Pasteur.

Pre-exposure prophylaxis (PrEP) is recommended for people in high-risk occupations (laboratory staff handling live rabies and related viruses) and for people whose professional or private activities may lead to direct contact with infected animals (animal disease control workers and gamekeepers).

In some areas, PrEP may be indicated before recreational activities or travel, and for people living in remote, high-rabies areas with limited local access to biological anti-rabies drugs.

Note that PrEP is not a replacement for PEP. Anyone who has had contact with a suspected rabid animal should still seek treatment after the contact.

Post-exposure prophylaxis (PEP) is the emergency response to rabies exposure. This prevents the virus from entering the central nervous system. PEP consists of:

  • Thoroughly wash wounds with soap and water for at least 15 minutes immediately after exposure;
  • a rabies vaccination; and
  • Administration of rabies immunoglobulin or monoclonal antibodies into the wound if indicated.

Exposure risk and indications for PEP

Depending on the severity of exposure, administration of a full course of PEP is recommended as follows:

Table: Contact categories and recommended post-exposure prophylaxis (PEP)

Categories of contact with suspected rabid animals
Post-exposure prophylactic measures

Category I – Touching or feeding animals, licking animals on intact skin (no exposure) Washing exposed skin surfaces, no PEP

Category II – Nibbling on uncovered skin, minor scratches or abrasions without bleeding (exposure) wound irrigation and immediate vaccination

Category III – single or multiple transdermal bites or scratches, contamination of mucous membranes or injured skin with saliva by animal licking, exposure by direct contact with bats (severe exposure) wound irrigation, immediate vaccination and administration of rabies immunoglobulin/monoclonal antibodies

NB: For Category II and III exposures, rabies vaccination for humans is required.

Vaccine quality

WHO recommends that all rabies vaccines for humans meet WHO standards.

The use of substandard rabies vaccines has caused public health problems in several countries.

Vaccine administration – intradermal (ID) vs. intramuscular (IM)

As detailed in the guidelines on PEP administration, WHO recommends moving from intramuscular (IM) to intradermal (ID) administration of rabies vaccines in humans.

Intradermal administration reduces the amount of vaccine required and the number of doses, reducing costs by 60-80% without compromising safety or efficacy.

A lower dose also helps patients adhere better to the recommended treatment.

WHO response

Rabies is included in the WHO Roadmap 2021–2030 for the global control of NTDs, which sets regional, progressive targets for the global strategic plan to end human deaths from dog-transmitted rabies by 2030 (see also: Zero to 30). This includes:

  • Improving access to rabies vaccines for humans through the efforts of WHO and its partners, the Vaccine Alliance Gavi, which included rabies vaccines for humans in its vaccine investment strategy for 2021-2025 (1)Despite pandemic-related delays, WHO is now working with GAVI to implement the programme in 2024.
  • Providing technical guidance supports countries in developing and implementing their national rabies eradication plans, with a focus on enhanced surveillance and reporting;
  • Encouraging countries to build the capacity of their One Health workforce by using rabies elimination programmes as a platform for cross-sectoral cooperation; and
  • Promoting the use of the multi-stakeholder forum United Against Rabies (UAR) (2)which was launched in collaboration with the WHO, the Food and Agriculture Organization (FAO) and the World Organization for Animal Health (WOAH, formerly OIE) to promote action and investment in rabies control.

References

  1. Vaccine Investment Strategy 2024. Gavi, the Vaccine Alliance. https://www.gavi.org/our-alliance/strategy/vaccine-investment-strategy-2024
  2. Together against rabies.