Rumors debunked online! The incubation period of rabies does not last for more than ten years, but there is still a risk of infection from being licked or scratched!

Recently, the news of passers-by being bitten by dogs has frequently been on the hot search. Can the incubation period of rabies really be as long as more than ten years? If the patient has been bitten by a dog in the past, is it too late to get vaccinated now? If a person has been vaccinated against rabies and is bitten again, does he need to be vaccinated again?

There are many theories about the incubation period of rabies, some say 20 years, and others say the longest incubation period can be up to 46 years, which has caused many people who have been bitten by dogs to fall into deep fear. The incubation period of rabies refers to the time from being bitten to the onset of the disease, which is generally 1 to 3 months, and it is rare for it to be more than 1 year.

The length of the incubation period of rabies depends on many factors, including the amount and virulence of the infected virus, the location and condition of the bite, and the physical condition of the bitten person. Generally speaking, the stronger the virulence of the virus, the greater the amount of infected virus, the closer the bite is to the head and face, and the lower the immunity of the bitten person, the shorter the incubation period of rabies will be. Currently, the longest incubation period with clear evidence from the World Health Organization (WHO) is 6 years.

How should you "save yourself" after being bitten by a small animal?
Scientific treatment methods after being bitten

Step 1: Clean the wound alternately with soapy water (or other weak alkaline detergent) and running water (or saline) for at least 15 minutes.

Step 2: Go to the designated rabies vaccination clinic in time, conduct a graded diagnosis of the wound, and complete the vaccination as soon as possible.

Can the rabies vaccine be given a few days later?

Given that the mortality rate of rabies is almost 100%, and standardized post-exposure prophylaxis is almost 100% effective, the length of the rabies incubation period before each person develops the disease is uncertain, so the sooner the rabies exposure is treated, the better! Although treatment a few days later may sometimes be effective, you should never take this risk.

Is vaccination the only response to rabies exposure?

It should be noted that post-exposure management of rabies is not simply vaccination. Post-exposure management of rabies includes timely wound treatment, rational use of rabies passive immunization agents, and rabies vaccination.

Only if you are bitten by a dog can you get rabies

The "Specifications for the Prevention and Treatment of Rabies Exposure (2023 Edition)" clearly states that the following situations all constitute rabies exposure and should be properly prevented and treated as soon as possible: being bitten or scratched by a rabid, suspected rabid, or rabies host animal whose health cannot be confirmed, licking mucous membranes, broken skin, or open wounds, or contact of mucous membranes with saliva or tissue of animals that may be infected with the rabies virus, all constitute rabies exposure.

The probability of contracting rabies varies with different exposure methods. The risk of rabies exposure is divided into three levels. Level I exposure refers to intact skin contact or licking, and only the exposed area needs to be cleaned. Level II exposure refers to light nibbling of exposed skin, or minor scratches and abrasions without obvious bleeding. It is a low-risk exposure. Although the probability of disease is not high, it is not a risk-free exposure. In similar situations, the wound should be treated carefully and the rabies vaccine should be administered in a timely manner.

How do we distinguish between level I exposure and level II exposure? Generally speaking, alcohol can be used to gently wipe the scratched area of ​​the skin at the time of the bite. If there is pain, it means that the skin is damaged, which belongs to level II exposure; if there is no pain and the skin only feels cool, then the possibility of skin damage is not high, which belongs to level I exposure. It should be noted that this method is only used at the time of injury. If you cannot make an accurate judgment, you should go to a medical institution for treatment. Level III exposure is a high-risk exposure, which refers to single or multiple penetrating skin bites or scratches; broken skin is licked; mucous membranes and open wounds are contaminated; or direct contact with bats. High-risk exposure requires not only wound treatment and vaccination, but also whether to use rabies passive immunization preparations based on the history of rabies vaccination. In addition, those who are confirmed to be level II exposed and severely immunocompromised, or when level II exposure is located on the head and face and the injured animal cannot be determined to be healthy, should also be treated according to level III exposure.

In addition to dogs, wild carnivorous mammals such as cats, badgers, raccoon dogs, wolves, foxes, and bats are also high-risk animals for rabies. If you are injured by these animals, you must go to a professional medical institution for treatment as soon as possible.

How to deal with re-exposure? Many people will encounter exposure after re-exposure, that is, after being bitten by a dog, they have received rabies vaccine or rabies immunization preparations, and then they are bitten by a dog again after a period of time. In this case, do you need to receive rabies vaccine or rabies immunization preparations again?

The guidelines recommend:

1. For those who have received a full course of vaccination, if they are exposed again within 3 months, if the injured animal is healthy and has been vaccinated, and can be observed for 10 days, the booster vaccination can be postponed on the premise of ensuring proper wound treatment;

2. Those who are exposed again more than 3 months ago need to receive 1 dose of vaccine on day 0 and day 3;

3. If a vaccine of uncertain efficacy was used, or the person was not fully vaccinated before, or the person was severely exposed to level III, a full vaccination should be completed after the next exposure.

The new guidelines also emphasize that as long as patients have received a full course of regular and qualified vaccines, no matter how long it has been since they were injured again, they do not need to be injected with passive immunization agents, and only need to undergo wound treatment and vaccination. Data show that the effect of re-boosting is still very good for those who were vaccinated 20 years ago.

Reference: "The incubation period of rabies is as long as more than ten years? Don't trust the animals that spread rabies?" Science rumor-busting platform, Healthy China

What you should know about preventing rabies