Can a "flower" on your arm prevent monkeypox? An article distinguishes monkeypox, smallpox, and chickenpox

Recently, topics related to "monkeypox" have been frequently searched, attracting widespread attention.

On May 21, the World Health Organization issued an alert on the monkeypox outbreak, stating that since cases have been found in several countries where the monkeypox virus is not endemic, as monitoring expands, more cases are likely to be found in countries where cases have been reported and other countries in the future, and the monkeypox virus will spread further.

The new crown virus has not yet subsided, and monkeypox has resurfaced. Many netizens have raised their own questions: Monkeypox, smallpox, and chickenpox all have pox in their symptoms, what is the difference? The smallpox vaccine can prevent monkeypox, so can the "flower planting" marks on my arm prevent it? Let's take a look!

It’s hard to tell the difference between monkeypox, smallpox and chickenpox. What are the differences between them?

1. All are infectious diseases caused by viral infection

Monkeypox, smallpox, and chickenpox are infectious diseases caused by infection with monkeypox virus, smallpox virus, and varicella-zoster virus respectively.

Viruses are divided into two types: DNA viruses and RNA viruses. DNA viruses are double-stranded, while RNA viruses are single-stranded. Single-stranded structures are less stable than double-stranded structures, so single-stranded RNA viruses are more likely to mutate during transmission. For example, the new coronavirus, which has not yet been eliminated, is an RNA virus. Monkeypox virus, smallpox virus, and varicella-zoster virus are all DNA viruses, but they are essentially three different types of viruses, except that monkeypox virus and smallpox virus are more closely related.

Monkeypox virus and smallpox virus are close relatives, belonging to the genus Orthopoxvirus of the Poxviridae family. The genome structures of the two are very similar, and there are many similarities in biological characteristics and pathogenicity, which can be understood as the same origin. The genus Orthopoxvirus also includes vaccinia virus, cowpox virus, camelpox virus, mousepox virus, etc.

2. Symptoms include rash

In terms of symptoms, the most similar thing between monkeypox, smallpox and chickenpox is that they all develop rashes on the body.

The rash caused by monkeypox usually begins within 1-3 days after the onset of fever and tends to be more concentrated on the face and limbs than on the trunk.

The rash caused by smallpox usually occurs during a 2-3 day prodromal period of high fever. The rash first appears on the oral and pharyngeal mucosa, then on the face and forearms, and then spreads centrifugally to the legs and trunk.

Chickenpox usually causes a rash within 24 hours of onset, which first appears on the face or trunk and has a centripetal distribution, rarely involving the palms and soles.

3. Different degrees of severity: smallpox > monkeypox > chickenpox

Common symptoms of monkeypox include fever, severe headache, swollen lymph nodes, back pain, muscle aches, fatigue, etc. Swollen lymph nodes are a unique feature of monkeypox compared to smallpox.

Complications of smallpox included bacterial infection of the skin and other organs, pneumonia, systemic sepsis, destructive arthritis and arthropathy in young children, corneal ulcers leading to blindness (most commonly in patients with trachoma), keratitis, osteomyelitis, and encephalitis, with a mortality rate of up to 30%. The most common sequelae among survivors were facial pockmarks, blindness, and limb deformities.

Monkeypox is less disfiguring than smallpox, but it also leaves permanent scars. Overall symptoms generally last 2 to 4 weeks. Most infected people recover within a few weeks, but some die from the severity of the disease. Severe cases are more common in children. Complications of monkeypox include secondary infection, bronchopneumonia, sepsis, encephalitis, and corneal infection leading to vision loss. The case fatality rate of monkeypox has historically been 0% to 11% in the general population and higher in young children. In recent years, the case fatality rate of monkeypox has been around 3%-6%.

Although chickenpox is also highly contagious, it is a self-limiting disease like monkeypox, and has an extremely low mortality rate. It is more common in infants and preschool children, and generally has a good prognosis and leaves no scars.

I have vaccine scars on my arms. Can I prevent monkeypox?

In order to prevent diseases, people will receive various vaccines, such as BCG vaccine, hepatitis B vaccine, measles vaccine, polio vaccine, etc., but there are usually only two types that can leave "flowers" (scars) on the arms, smallpox vaccine and BCG vaccine.

However, having a vaccine scar on your arm does not necessarily protect you from monkeypox.

As mentioned earlier, monkeypox virus, smallpox virus, vaccinia virus, cowpox virus, camelpox virus, and mousepox virus are all orthopoxviruses. In fact, orthopoxviruses have the characteristic of "cross immunity", that is, infection with any of these viruses will make the infected person immune to other poxviruses. For example, the traditional smallpox vaccine that people are familiar with is prepared with cowpox virus.

According to WHO data, the smallpox vaccine is 85% effective against the monkeypox virus. In addition, data show that people who have received the smallpox vaccine may have fairly comprehensive protection against smallpox infection for up to 10 years, protection against symptomatic infection may last for 30 years, and protection against the fatal consequences of smallpox may last even longer.

Whether the smallpox vaccine is still effective in preventing smallpox and monkeypox today may require more research data. Moreover, most people under 40 have not received the smallpox vaccine.

In 1980, the World Health Organization announced that smallpox had been eradicated and recommended that routine smallpox vaccination be stopped. By 1983, almost all countries had stopped routine smallpox vaccination. In 1981, China abolished the method of universal smallpox vaccination, but some regions may have delayed it. For example, Beijing completely stopped smallpox vaccination in 1984 in order to consolidate the effect.

Therefore, the scars on the arms of most Chinese people born after the 1980s are from the BCG vaccine, which prevents tuberculosis, rather than the smallpox vaccine. People born in a time and region where both vaccines were administered may have scars from both BCG and smallpox vaccines on their arms.

By the way, people who had chickenpox as a child or received the chickenpox vaccine are not immune to monkeypox.

How to prevent monkeypox if you haven't been vaccinated against smallpox?

Many people may have a question: since smallpox has been eradicated, does China still stockpile smallpox vaccines?

According to relevant media reports, Tan Wenjie, an expert from the Chinese Center for Disease Control and Prevention, said that my country has been storing emergency smallpox vaccines for a long time and can provide millions of smallpox vaccines for emergency vaccination at any time. In addition, the traditional smallpox vaccine is prepared with cowpox virus strains. China has safely sealed the "cowpox", so it is not difficult to produce smallpox vaccines.

Therefore, those who have not received the smallpox vaccine do not need to worry too much. As the monkeypox epidemic changes, the government will make arrangements for whether and when the whole population should receive the smallpox vaccine.

For individuals, prevention of monkeypox infection requires avoiding unprotected contact with wild animals, especially those that are sick or dead. In addition, all foods containing animal meat or animal parts must be thoroughly cooked before consumption.

Since the beginning of history, humans have been fighting against viruses. Monkeypox virus is not the first and will not be the last. At present, instead of worrying and being anxious, it is better to take precautions in daily life.

References:

[1] Nigam P, Earl PL, Americo JL, et al. DNA/MVA HIV-1/AIDS vaccine elicits long-lived vaccinia virus-specific immunity and confers protection against a lethal monkeypox challenge. Virology. 2007;366(1):73-83.

[2] Hashizume S. A new attenuated strain of vaccinia virus, LC16m8: basic information. J Clin Virol. 1975;3:229-235.

[3] Stanford MM, McFadden G, Karupiah G, et al. Immunopathogenesis of poxvirus infections: forecasting the impending storm. Immunol Cell Biol. 2007;85(2):93-102.

[4] World Health Organization. WHO Expert Committee on Smallpox. Geneva, Switzerland: World Health Organization; 1964.

[5] Rao AR. Smallpox. Bombay, India: The Kothari Book Dept; 1972.

[6] Marsden JP, Hurst EW. Acute perivascular myelinoclasis (“acute disseminated encephalomyelitis”) in smallpox. Brain. 1932;55: 181-225.

[7] Moore ZS, Seward JF, Lane JM. Smallpox. Lancet. 2006;367(9508): 425-435.

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