news

Ealry in this month, the World Health Organization (WHO) announced that monkeypox cases have surged in the Democratic Republic of Congo (DRC) and several African countries, constituting a public health emergency of international concern.
As early as two years ago, monkeypox virus was recognized as an international public health emergency due to its spread in multiple countries, including China, where the virus had never been prevalent before. However, in May 2023, as global cases continued to decrease, this state of emergency was lifted.
The monkeypox virus has hit again, and although there have been no cases in China yet, sensational claims that the virus is transmitted through mosquito bites have flooded Chinese social media platforms.
What are the reasons behind WHO’s warning? What are the new trends in this epidemic?
Will the new variant of monkeypox virus be transmitted by droplets and mosquitoes?

What are the clinical characteristics of monkeypox?
Is there a vaccine to prevent monkeypox and a medicine to treat it?
How should individuals protect themselves?

Why is it receiving attention again?
Firstly, there has been a significant and rapid increase in reported cases of monkeypox this year. Despite the continuous occurrence of monkeypox cases in DRC for many years, the number of reported cases in the country has significantly increased in 2023, and the number of cases so far this year has exceeded last year, with a total of over 15600 cases, including 537 deaths. Monkeypox virus has two genetic branches, I and II. Existing data suggests that the clinical symptoms caused by branch I of monkeypox virus in DRC are more severe than those caused by the 2022 epidemic strain. At present, at least 12 African countries have reported cases of monkeypox, with Sweden and Thailand both reporting imported cases of monkeypox.

Secondly, the new cases seem to be more severe. There are reports that the mortality rate of monkeypox virus branch I infection is as high as 10%, but an expert from the Belgian Institute of Tropical Medicine believes that the cumulative case data over the past 10 years shows that the mortality rate of branch I is only 3%, which is similar to the mortality rate of branch II infection. Although the newly discovered monkeypox virus branch Ib has human to human transmission and spreads rapidly in specific environments, epidemiological data on this branch is very limited, and DRC is unable to effectively monitor virus transmission and control the epidemic due to years of war and poverty. People still lack understanding of the most basic virus information, such as the differences in pathogenicity among different virus branches.
After re declaring monkeypox virus as a public health emergency of international concern, WHO can strengthen and coordinate international cooperation, especially in promoting access to vaccines, diagnostic tools, and mobilizing financial resources to better implement epidemic prevention and control.
New characteristics of the epidemic
Monkeypox virus has two genetic branches, I and II. Before 2023, IIb was the main virus that was prevalent worldwide. So far, it has caused nearly 96000 cases and at least 184 deaths in 116 countries. Since 2023, the main outbreaks in DRC have been in the Ia branch, with nearly 20000 suspected cases of monkeypox reported; Among them, 975 suspected cases of monkeypox deaths occurred, mostly in children aged 15 years or younger. However, the newly discovered monkeypox virus Ⅰ b branch has now spread to four African countries, including Uganda, Kenya, Burundi and Rwanda, as well as Sweden and Thailand, two countries outside Africa.
Clinical manifestation
Monkeypox can infect children and adults, usually in three stages: latent period, prodromal period, and rash period. The average incubation period for newly infected monkeypox is 13 days (range, 3-34 days). The prodromal phase lasts for 1-4 days and is typically characterized by high fever, headache, fatigue, and usually lymph node enlargement, especially in the neck and upper jaw. Lymph node enlargement is a characteristic of monkeypox that distinguishes it from chickenpox. During the eruption period lasting 14-28 days, the skin lesions are distributed in a centrifugal manner and divided into several stages: macules, papules, blisters, and finally pustules. The skin lesion is hard and solid, with clear boundaries and a depression in the middle.
Skin lesions will scab and shed, resulting in insufficient pigmentation in the corresponding area after shedding, followed by excessive pigmentation. The patient’s skin lesions range from a few to several thousand, mainly located on the face, trunk, arms, and legs. Skin lesions often occur on the palms and soles of the feet, which is a manifestation of monkeypox different from chickenpox. Usually, all skin lesions are at the same stage, which is another characteristic that distinguishes monkeypox from other skin symptomatic diseases such as chickenpox. Patients often experience itching and muscle pain. The severity of symptoms and duration of disease are directly proportional to the density of skin lesions. This disease is most severe in children and pregnant women. Monkeypox usually has a self limiting course, but often leaves behind adverse appearances such as facial scars.

Transmission route
Monkeypox is a zoonotic disease, but the current outbreak is mainly transmitted between humans through close contact with monkeypox patients. Close contact includes skin to skin (such as touching or engaging in sexual activity) and mouth to mouth or mouth to skin contact (such as kissing), as well as face-to-face contact with monkeypox patients (such as talking or breathing close to each other, which may produce infectious respiratory particles). At present, there is no research indicating that mosquito bites can transmit monkeypox virus, and considering that monkeypox virus and smallpox virus belong to the same genus of orthopoxvirus, and smallpox virus cannot be transmitted through mosquitoes, the possibility of monkeypox virus transmission through mosquitoes is extremely low. The monkeypox virus may persist for a period of time on clothes, bedding, towels, items, electronic devices, and surfaces that monkeypox patients have come into contact with. Others may become infected when they come into contact with these items, especially if they have any cuts or abrasions, or if they touch their eyes, nose, mouth, or other mucous membranes before washing their hands. After coming into contact with potentially contaminated items, cleaning and disinfecting them, as well as cleaning hands, can help prevent such transmission. The virus may also be transmitted to the fetus during pregnancy, or transmitted through skin contact at birth or after birth. People who come into physical contact with animals carrying the virus, such as squirrels, may also be infected with monkeypox. Exposure caused by physical contact with animals or meat may occur through bites or scratches, or during activities such as hunting, skinning, trapping, or preparing meals. Eating contaminated meat that has not been thoroughly cooked can also lead to virus infection.
Who is at risk?
Anyone who has close contact with patients with monkeypox symptoms may be infected with the monkeypox virus, including healthcare workers and family members. Children’s immune systems are still developing, and they play and interact closely. In addition, they do not have the opportunity to receive the smallpox vaccine, which was discontinued more than 40 years ago, so the risk of infection is relatively high. In addition, individuals with low immune function, including pregnant women, are considered high-risk populations.   
Treatment and Vaccines
There are currently no drugs available to treat monkeypox virus, so the main treatment strategy is supportive therapy, which includes rash care, pain control, and prevention of complications. Two monkeypox vaccines have been approved by WHO but have not been launched in China. They are all third-generation attenuated smallpox virus vaccines. In the absence of these two vaccines, WHO also approved the use of the improved smallpox vaccine ACAM2000. Gao Fu, an academician of the Institute of Microbiology of the Chinese Academy of Sciences, published a work in Nature Immunology in early 2024, suggesting that the “two in one” recombinant protein vaccine of monkeypox virus designed by the multi epitope chimerism strategy guided by the antigen structure can protect the two infectious virus particles of monkeypox virus with a single immunogen, and its neutralizing capacity for monkeypox virus is 28 times that of the traditional attenuated live vaccine, which may provide a safer and scalable alternative vaccine scheme for the prevention and control of monkeypox virus. The team is collaborating with Shanghai Junshi Biotechnology Company to advance vaccine research and development.