Rabies is a viral disease that affects the central nervous system and is almost always fatal once symptoms appear. However, a handful of people have managed to survive rabies despite the odds. In this article, we will explore the question of how someone can survive this deadly disease.
What is rabies?
Rabies is caused by a virus in the genus Lyssavirus. It is spread through contact with the saliva of an infected animal, usually through a bite. The rabies virus travels from the wound site to the peripheral nerves, eventually making its way to the brain and central nervous system.
Once in the brain, the virus causes inflammation and dysfunction, leading to the symptoms associated with rabies. After the onset of symptoms, rabies has an almost 100% fatality rate if left untreated.
Some key facts about rabies:
- Rabies infects mammals, most often those in the order Carnivora (dogs, cats, raccoons, etc). Bats are the most common source of human rabies infections in the Americas.
- The incubation period between exposure and symptom onset is typically 1-3 months but can range from under a week to over a year.
- Initial symptoms are fever, headache, general discomfort. As the disease progresses, neurological symptoms arise including anxiety, confusion, hallucinations, paralysis, and hydrophobia (fear of water).
- Death usually occurs within days or weeks of neurological symptom onset due to respiratory failure.
- Rabies can only be diagnosed conclusively by examining the brain tissue after death.
So how is it possible for someone to survive this essentially 100% fatal disease?
Rabies Vaccines
One way people can survive rabies is if they receive vaccination against the virus shortly after exposure. Rabies vaccines work by stimulating the immune system to produce antibodies that can neutralize the rabies virus.
Pre-exposure prophylaxis
Individuals at high risk of rabies exposure, such as veterinarians, animal handlers, and lab workers, are recommended to receive pre-exposure prophylaxis (PrEP). This involves receiving multiple doses of the rabies vaccine over a period of weeks.
PrEP primes the immune system to mount a faster antibody response if exposed to rabies. Studies show that PrEP confers protection against rabies for at least 2 years with antibody titers remaining elevated for over 10 years in most vaccinated people.
Post-exposure prophylaxis
Post-exposure prophylaxis (PEP) involves promptly administering a dose of rabies vaccine after a suspected rabies exposure, along with a dose of rabies immune globulin (antibodies obtained from vaccinated human donors).
PEP is highly effective at preventing the onset of rabies if administered soon after exposure – within 24 hours optimally. The faster PEP is given, the better the chances of success.
According to the CDC, there have been over 55,000 people in the United States receive PEP to prevent rabies since 1980. When administered properly, PEP has nearly a 100% success rate in preventing rabies.
Milwaukee Protocol
In rare cases, people have survived rabies even after the onset of symptoms, without having received any pre- or post-exposure prophylaxis. This is only possible through an experimental treatment protocol known as the Milwaukee Protocol.
History
The Milwaukee Protocol was first developed in 2004 by Dr. Rodney Willoughby of the Children’s Hospital of Wisconsin, after an unvaccinated 15-year-old girl named Jeanna Giese arrived at the hospital with rabies symptoms.
Dr. Willoughby hypothesized that putting Giese into a coma and administering antiviral drugs might help support her until her immune system could mount an antibody response and clear the virus.
Amazingly, after spending 31 days in the coma and enduring numerous complications, Giese survived and eventually made a full recovery. This marked the first documented case of a human surviving rabies without vaccination.
Treatment
The Milwaukee Protocol involves inducing a therapeutic coma and administering a cocktail of antiviral medications including:
- Ketamine – anesthetic that reduces central nervous system activity
- Midazolam – sedative used to maintain coma state
- Ribavirin and/or amantadine – antivirals that may inhibit rabies virus replication
In addition, patients are treated with hemodynamic support, anticonvulsants, antipyretics, and electrolyte replacement as needed while comatose.
The premise is that the coma state may protect the brain from damage while the antivirals work to slow down replication of the virus until the immune system can catch up.
Effectiveness
Since Giese’s case, dozens of other patients with rabies symptoms have been treated using the Milwaukee Protocol worldwide. However, most attempts have failed and the protocol’s overall effectiveness remains very low.
As of 2016, there were only 8 documented cases of unvaccinated rabies survivors out of more than 85 Milwaukee Protocol attempts globally. Most patients succumb to organ failure, complications from prolonged intensive care, or persistent viral infection.
Nonetheless, the fact that any unvaccinated patients have survived symptomatic rabies is remarkable. Ongoing study of these rare cases provides insight into rabies immunity that may advance the development of more reliable treatments in the future.
Case Studies
Let’s take a closer look at two of the rare documented cases where people survived rabies in the absence of any pre- or post-exposure prophylaxis.
Jeanna Giese
Jeanna Giese was the first patient ever to survive rabies without prior vaccination. In 2004, the 15-year-old from Wisconsin was bitten by a bat and subsequently developed symptoms including limb tremors, slurred speech, and abnormal behavior.
Once hospitalized, Giese’s condition rapidly deteriorated to the point she could no longer walk, talk, or eat on her own. At this stage, rabies is normally fatal within days.
Dr. Willoughby decided to try inducing a coma along with antiviral drugs. Giese spent 31 days unconscious in intensive care. She gradually regained neurological function, although she endured months of rehabilitation to relearn basic abilities like talking and feeding herself. Her immune system was eventually able to clear the virus entirely.
In 2005, Jeanna Giese walked out of the hospital as the first documented survivor of the Milwaukee Protocol. She went on to graduate high school, attend college, and raise awareness about rabies prevention.
Precious Reynolds
In 2011, eight-year-old Precious Reynolds of California also beat the odds and survived a rabies infection without vaccination.
Reynolds was bitten by a feral cat while playing outside her house. By the time she started developing neurological symptoms a month later, it was too late for PEP vaccines to work. Her doctors used the Milwaukee Protocol as a last resort.
After spending nearly two weeks in a medically-induced coma, Reynolds awoke on her ninth birthday. She eventually regained normal neurological function aside from some minor memory issues and vision impairment.
Like Giese, Reynolds’s immune system managed to overcome the rabies virus after the Milwaukee Protocol kept her alive during the acute infection phase. She became the third patient ever to survive symptomatic rabies untreated.
Key Factors for Survival
Due to the very limited number of rabies survivors without vaccination, it’s difficult to draw definitive conclusions about why these patients lived while most die. However, some patterns have emerged among survivors that may provide clues.
Young age
Most untreated rabies survivors were under 18 at the time of infection. Children and teens tend to have more robust immune responses compared to adults. Their bodies may be better equipped to counteract the rabies virus with antibody production once given the chance.
Good health
In general, the rare survivors were healthy before their rabies infection with no major underlying conditions. Being young and otherwise healthy improves their odds of withstanding intensive medical interventions like induced comas.
Prompt hospitalization
Seeking medical care promptly at the onset of symptoms leads to earlier administration of the Milwaukee Protocol. The sooner the virus can be slowed down, the greater chance the immune system has to catch up later on.
Genetic factors?
Some scientists speculate genetics or other natural immunological advantages may predispose a tiny subset of people to overcome rabies more effectively. But there’s no concrete evidence pinpointing inherited traits related to rabies survival yet.
New possibilities
As medical knowledge advances, new possibilities emerge for boosting the immune response against the rabies virus. For example, bioengineered monoclonal antibody therapies may someday provide an alternative method of neutralizing rabies viruses in symptomatic patients. More survivors could change perceptions of rabies as a guaranteed death sentence.
Prevention Is Key
While a few extraordinary cases prove it’s possible to survive rabies without vaccination, this outcome is extremely unlikely. Overall, the Milwaukee Protocol has had a Pet vaccination
Keeping pet dogs and cats up-to-date on their rabies vaccinations minimizes the risk of transmission. Many areas legally require routine rabies immunization for domestic animals.
Avoid wildlife
Do not touch or handle any wild mammals, particularly bats. Teach children not to approach unknown animals. Call animal control if you see wildlife behaving strangely.
Bite precautions
Thoroughly wash any animal bite wound immediately with soap and water. Capture or isolate the animal safely if possible for rabies testing. Promptly seek medical care to assess the need for PEP.
Travel precautions
Research rabies risks and appropriate precautions before traveling to endemic countries. Consider PrEP vaccination if planning activities with increased exposure risk.
The Future of Rabies Treatment
While rabies ultimately has a poor prognosis, researchers continue working to improve the odds for infected patients. New possibilities being explored include:
- Optimizing Milwaukee Protocol drug cocktails
- Combining antivirals with immunotherapy
- Bioengineered monoclonal antibodies
- Novel therapies to suppress lethal inflammation and prevent brain damage
- Gene editing techniques to knock out viral DNA
Studying rare rabies survivors also gives clues into how humans might develop natural resistance. Although the disease remains deadly in most cases today, breakthrough discoveries could reshape treatment and boost survival rates someday.
Conclusion
Rabies remains extremely deadly once symptoms manifest, killing nearly everyone who contracts the virus. However, vaccination introduced promptly after an exposure provides highly effective prevention.
In rare instances, patients who receive intensive medical intervention soon after symptom onset – especially the Milwaukee Protocol – also manage to survive, giving hope that rabies may eventually become a less feared and fatal disease. By continuing to study rabies survivors, researchers edge closer towards unraveling the mysteries surrounding immunity and developing improved treatment options for this ancient scourge.