Shishuo Xinyu丨The longest incubation period of rabies is 19 years?

One news topic spread two extremely wrong information!

Discussion ①: Does China have the longest rabies incubation period in the world?

A patient in Shengzhou was diagnosed with rabies, but he denied that he had been bitten or scratched by a cat or dog. Only his wife said that he was bitten by a dog a few years ago. Then the news appeared that "the longest incubation period of rabies can be up to 19 years" (see the picture below).

Is this "incubation period" correct? Let's not discuss whether my wife's recollection is biased, and let's not consider the answer provided by the research. Let's first talk about the "shortest" and "longest" incubation periods of rabies in the data released in China.

After checking various information, I found that the statement that the incubation period can reach 19 years is really conservative in China.

I have previously criticized the lack of reliable evidence to support the claim in our country's medical textbook "Infectious Diseases" that the incubation period of rabies can be "up to 10 years or more", but the textbook has not been revised so far. Therefore, domestic doctors may have received incorrect knowledge since school, and if they have not received special training after becoming doctors, they will certainly accept this statement.

What is even more shocking is that a study published in my country on the epidemiological analysis of rabies in central China mentioned that the incubation period of the included cases ranged from "3 days to 18,406 days (about 50 years)" (see figure below)!

If this is true, it can really be said that "once bitten by a dog, you can't escape for decades"!

Discussion ②: What is China’s vaccine and passive immunization program?

Although the patient mentioned in the news was said to have died in a subsequent follow-up visit, the news still very considerately provided popular science information about rabies vaccines and immunoglobulins.

The news mentioned two points:

1. If you are scratched or injured by a stray cat or dog, you should also be injected with rabies immunoglobulin;

2. Rabies vaccination should be given within 24 hours after being bitten or scratched, usually within six months of vaccination. If bitten by a suspicious animal again, no more vaccination is necessary.

It is very interesting that in today's world where rabies fear is so rampant, the country may administer "70 to 80 million doses of rabies vaccine each year" (assuming each person receives a maximum of 5 doses), and "more than 10 million people" receive rabies vaccine each year), ranking first in the world.

The picture was purchased from: depositphotos

However, one issue seems to have been forgotten in this part - "exposure level" and "professional advice".

In fact, these two key popular science contents are inaccurate. If the first point (protein for vaccination through scratching) may only lead to the abuse of vaccines and passive immunization preparations, the second point may put people who are exposed to rabies virus again in danger.

【Key points of scientific prevention of rabies】

1. Incubation period: The incubation period of rabies is generally within "1 to 3 months", and a few may be less than 1 week or more than 1 year. However, the "longest incubation period" with conclusive evidence is currently 8 years. Cases of more than 10 years are basically based on "self-report" or "epidemiological investigation and judgment."

2. How to use vaccines and immunoglobulins (see the picture below):

You should never assume that you must get vaccinated or given immunoglobulin if you are exposed to stray animals. The determination method is as follows (emphasize: the necessity of vaccination must be determined by professionals, not by yourself):

① Animal prerequisite: (even if it is a stray animal) "unknown vaccination history" or has not been vaccinated against rabies. If it is a cat, dog or ferret that has been vaccinated in the past, the "10-day observation method" can be used to observe while being vaccinated;

The picture was purchased from: depositphotos

②Human prerequisite: full course of rabies vaccination more than "within 3 months", and never completed "full course of rabies vaccination";

③Exposure level: Level 2 or Level 3 exposure. The simplest understanding is that the former is "visible skin lesions" and the latter is "hemorrhagic lesions". Vaccination is "needed" in these two situations (touching through pants, touching animal food bowls, and being sprayed by animals when passing by animals are not necessary); in addition, if level 2 exposure occurs in nerve-rich areas such as hands, feet, face, genitals, or exposure to bats, it is "treated as level 3 exposure";

④ Passive immunization preparations: only needed for "level 3 exposure", including horse serum, human immunoglobulin, and monoclonal antibodies, ranked from low to high in price. If you have received a "full course" of rabies vaccination in the past, you do not need to receive passive immunization preparations regardless of the level of exposure;

⑤ Re-exposure: No need to repeat vaccination within 3 months after the full vaccination, regardless of whether the "pre-exposure" or "post-exposure" program is used. If it exceeds 3 months, "2 doses" of rabies vaccine are required, with an interval of "3 days", regardless of the time of the previous round of rabies vaccination;

3. Wound treatment: Wound treatment is definitely not washing with running water, but should follow the following steps:

① Use soapy water (or other weak alkaline cleaning agents) and running water with a certain pressure to wash each bite and scratch wound alternately for at least 15 minutes;

② After thorough rinsing, use diluted iodine tincture (0.025%-0.05%), benzalkonium chloride (0.005%-0.01%) or other skin and mucous membrane disinfectants with "virus inactivation effect" to disinfect or disinfect the inside of the wound;

The picture was purchased from: depositphotos

③ After the wound is cleaned and disinfected, and rabies passive immunization preparations are used as needed for at least two hours, subsequent "surgical treatment" should be carried out according to the situation.

The above is the correct information and handling method. Simply put, the mistakes in the news are "exaggerating the incubation period" and "misstatement of the application methods of vaccines and passive immunization preparations."

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=丸= Disclaimer: This article was created out of personal interest, only to allow more ordinary people to have a clearer understanding of vaccines. The content and views do not represent any organization, unit, or institution, and have not accepted any form of sponsorship. All illustrations are from public online platforms and purchased at self-funded expenses. If the content is incorrect, please do more self-criticism (not).