ADC Reviews

Monkeypox infectivity and mode of transmission


Monkeypox, a smallpox-like virus, is causing global alarm.

On July 23, the World Health Organization (WHO) declared monkeypox a global public health emergency (PHEIC). Over the past two weeks, monkeypox has infected more than 10,000 people globally, mainly in the Americas and Europe.

Although the symptoms of this round of monkeypox are mild and the transmission is far less than that of the new crown, there are more than 13% of asymptomatic infections, so the prevention of monkeypox cannot be taken lightly. Although monkeypox is similar to smallpox, it has a strong immune evasion ability. At present, people over 42 years old have basically been vaccinated against smallpox. However, after many years, whether the protective power of the vaccine can be awakened still needs to be studied. However, the existing smallpox vaccine still has certain protection against severe monkeypox infection.

It has appeared in more than 80 countries. How contagious is monkeypox?

Since it was discovered in mid-May and declared as PHEIC by WHO in late July, monkeypox outbreaks have now appeared in more than 80 countries. People still in the midst of the Covid-19 pandemic can’t help but wonder if monkeypox will spread as quickly and as unpredictably as Covid-19.

The speed of monkeypox transmission in the population still needs a process of understanding, but the current mode of transmission is mainly through close contact, and transmission through respiratory secretions does not seem to be common, so monkeypox is definitely less infectious than the new crown, but in special populations (close, continuous physical contact with a monkeypox patient) transmission rates are high.

The proportion of asymptomatic patients infected with monkeypox virus exceeds 13%, and its symptoms are often “atypical” and are often mistaken for other diseases, such as venereal diseases and new crowns, so “the risk of hidden transmission is extremely high.”

Although the current spread of monkeypox mainly occurs in men who have sex with men, there have been reports of cases in children and women, mostly through close family contact and care, such as sharing bedding and clothing can also transmit monkeypox virus.

Since monkeypox infected patients may go directly to some STD clinics and dermatology clinics instead of specialized infectious disease hospitals for treatment, this may lead to an increased chance of medical care infections. 4 For these medical institutions and departments, it is very necessary to focus on publicity and strengthen protection awareness. Wearing masks and strict hand disinfection are all very necessary and effective protective measures.

Similar to chickenpox, monkeypox is contagious from the onset of symptoms to the scab. Therefore, it is also important to properly dispose of related medical waste and prevent the occurrence of hospital infection.

Is the smallpox vaccine effective against monkeypox?

As the only microorganism that has been eradicated by humans, smallpox was declared extinct by the WHO in 1980, and babies born since then are no longer vaccinated against smallpox. If monkeypox is similar to smallpox, can people who have been vaccinated against smallpox not be afraid of monkeypox virus?

Several scientists said that conclusions cannot be drawn arbitrarily. After all, it has been many years since the smallpox vaccination. Whether and to what extent it can awaken its protective power in the body still needs to be studied. But what is clear is that the vaccine used for smallpox is indeed useful against monkeypox. Past data from Africa show that the smallpox vaccine is at least 85% effective in preventing monkeypox.

Monkeypox can cause fever, headache, muscle aches, back pain, swollen lymph nodes, general malaise, fatigue and severe rashes. And in remote areas with underserved health care, monkeypox can kill up to 11 percent of those infected. In contrast, most people who received the smallpox or monkeypox vaccine had only mild reactions, such as mild fever, tiredness, swollen glands, and redness and itching at the vaccination site.

Since monkeypox is similar to smallpox, is it possible for people to eliminate monkeypox like smallpox? It doesn’t seem easy.

Smallpox spread across species to humans no earlier than 15,000 years ago, with traces of smallpox infection left on Egyptian mummies 5,000 years ago. Humans can eliminate smallpox because of several conditions.
First, humans are the only known virus host;
Second, there is no asymptomatic carrier status;
Third, effective vaccines can be used;
Fourth, vaccination can prevent or improve disease outcomes.

In fact, scientists isolated the monkeypox virus as early as 1970. At that time, it was found that it could be transmitted in humans, apes, and monkeys. Later, it was found that it could survive in other animals. Today, monkeypox virus has been found to exist in a significant proportion of asymptomatic infections, making it nearly impossible to eradicate monkeypox virus.

Although the symptoms of monkeypox and smallpox are similar, the severe and fatality rate of this outbreak is very low, and smallpox used to be one of the infectious diseases with the highest mortality rate. At present, there is no specific treatment approved for monkeypox virus infection internationally, but there are several antiviral drugs used for the treatment of smallpox, such as cidofovir and immunoglobulin, which may be helpful for the treatment of monkeypox infection.