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core points:

• the current monkeypox epidemic in africa is dominated by virus clade ib, which is prevalent in urban areas of the democratic republic of the congo. the main modes of transmission are close contact and sexual transmission. due to the relatively backward medical facilities in the democratic republic of the congo, the monkeypox epidemic is difficult to effectively control locally.

• according to predictions from mathematical models, monkeypox will not cause a large-scale epidemic worldwide.

• monkeypox and smallpox are not the same thing. first, the mortality and infectivity of monkeypox are much weaker than that of smallpox; second, there are currently sufficient and effective methods to prevent or treat monkeypox.

in august 2024, the world health organization (who) declared that the monkeypox epidemic constituted a "public health emergency of international concern (pheic)". after two years, monkeypox was designated as a public health emergency of international concern for the second time.

could resurgent monkeypox cause a global pandemic? tencent news "let's laoke" talked with professor jin dongyan, a virologist and professor at the school of biomedical sciences, li ka shing faculty of medicine, the university of hong kong, to conduct a systematic discussion around the current monkeypox epidemic.

1. the current epidemic in africa is mainly branch type ib, which is only prevalent in some areas and will not spread on a large scale in china.

question: in july 2022, who declared that the monkeypox epidemic constituted a "public health emergency of international concern." two years later, what are the characteristics of this wave of monkeypox epidemic?

jin dongyan (professor and virologist, school of biomedicine, li ka shing faculty of medicine, university of hong kong):there are many different issues surrounding the current epidemic situation.

first, monkeypoxthere are currently two large branches, namely branch i and branch ii, where branch i includes branch ia and branch ib, and branch ii includes branch iia.(editor's note: it has only been found in epidemics in the united states in 2003 and liberia in 1970)and branch iib, this time branch ib appears.

the situations of these strains are very different. branch ii is used throughout the world fordiffuse fashion, mainly concentrated among gay men. monkeypox was designated a "public health emergency of international concern" by the world health organization in 2022 due to a global outbreak of clade iib, although it is no longer a major event(editor's note: on may 12, 2023, who announced that the monkeypox epidemic no longer constitutes a "public health emergency of international concern"), but it still poses a certain degree of threat around the world. fortunately, we have enough "weapons" to deal with it.the epidemic characteristics, transmission characteristics, pathogenicity and transmission routes of clade iib all indicate that it does not currently have the risk of causing a very large-scale worldwide pandemic.

monkeypox virus

branch iib is prevalent in small numbers all over the world, including in my country. if testing is done more frequently and monitoring is done well, it is very likely to be detected.

clade i used to be mainly prevalent in individual countries in africa, especially in the democratic republic of congo for a long time.(editor's note: monkeypox is caused by the orthopox virus and was first discovered in humans in the democratic republic of the congo in 1970. the disease is believed to be endemic in central and west african countries).

type ia monkeypox virus is mainly prevalent in some rural areas of the democratic republic of the congo and is basically endemic.first of all, the fatality rate of type ia is relatively high. according toworld health organizationthe estimate may reach 3.6%; secondly, type iathe main communication characteristics areit is prevalent on a small scale in rural areas near forests and is related to contact between humans and animals. it is rarely prevalent in urban areas.

type ib is a newly discovered strain. how big is it? can be found nowthere are approximately 18,000 confirmed cases, of which 600 have died.(editor's note: the latest data, as of september 8 this year, the democratic republic of the congo has the most cases, with 21,835 suspected and confirmed cases and 717 deaths). what are the characteristics of type ib? nowadays, it is mainly spread through family units and through close contact between people and sexual contact with same-sex or opposite-sex people.unlike type ia, it spreads more in cities.

when it comes to the mortality rate of ib, you have to compare it with whom. the fatality rate of type iib strains circulating in 2022 will be less than 0.1%.symptoms are also relatively mild. a mortality rate of less than 0.1% means that it is roughly on the same level as seasonal influenza, but the number of infections cannot be compared. the number of people infected by seasonal influenza is thousands of times that of type iib monkeypox.

the fatality rate of type ia is 3.6%, and according to current statistics,the fatality rate of type ib is about less than 1%, so the fatality rate is lower than that of type ia and higher than that of type iib.

in addition to sexual contact transmission, in terms of the scale of type ib transmission, it is still a sporadic epidemic, unlike smallpox, which can be transmitted through droplets or aerosols similar to respiratory infectious diseases (editor's note: the world health organization has previously mentioned that the mode of transmission of monkeypox includes close face-to-face contact with monkeypox patients (such as talking or breathing very close to each other, which may produce infectious respiratory particles)). however, judging from various model experiments of type iib monkeypox, the respiratory tract transmission method is basically not applicable, and it is not suitable for type i either.judging from the current situation, there are no confirmed cases of respiratory transmission or aerosol transmission.

epidemiological characteristics, pathogenesis, clinical diagnosis and treatment of monkeypox. a. the transmission routes of monkeypox include between animals, between animals and between people; b. clinical symptoms usually appear after infection with monkeypox; c. the symptoms of monkeypox infection depend on different immune status and clinical treatment plans. may vary and, as shown in the table, can include fever, fatigue, headache, etc. image source: junjie lu, hui xing and chunhua wang et al. mpox (formerly monkeypox): pathogenesis, prevention, and treatment. signal transduction and targeted therapy. 2023. vol. 8. doi: 10.1038/s41392-023-01675-2.

q: do we have the ability to deal with monkeypox right now? will we have another wave of the pandemic?

jin dongyan:the world is now very concerned about the possible impact of type ib. some scholars who do public health mathematical models,based on its epidemic characteristics in the democratic republic of the congo, we applied the model to the united states and concluded that monkeypox type ib is not enough to threaten the united states.——even if the virus is introduced into the united states, according to mathematical model prediction research and taking many factors into consideration, it is unlikely to cause a major epidemic in the united states.

based on the current situation and calculations based on many factors, previous literature and other aspects, it is estimated that the mortality rate of type ib does not exceed 1%. however, the democratic republic of the congo is one of the most backward countries in the world, with very poor medical facilities and other conditions.there are no conditions for vaccination, so in this case, the mortality rate caused by type ib is about 1%.still much lower than type ia.if the same disease occurs in developed countries, this is probably not the case.

image source: visual china

the three branches of monkeypox ia, ib and iib are still endemic in the democratic republic of the congo and have entered some nearby african countries in small quantities. this is why the world health organization and the african centers for disease control and prevention have the reason is very important, but it is still distributed.

outside africa, there are two other cases, one in sweden and the other in thailand, which are also relatively small.in africa, due to incomplete basic medical facilities and the inability to widely use vaccines, the control of the epidemic has been limited.however, the current data from the democratic republic of the congo cannot indicate that an uncontrollable monkeypox epidemic has occurred in africa. just because the who has declared it a public health emergency of international concern does not mean that everyone is facing a very big danger. it just requires public attention. the current scale of monkeypox or the scope of its impact is still very limited.will monkeypox immediately have a huge impact on countries around the world? i can say relatively clearly that based on the existing evidence, it is not possible.

question: we are currently facing three different branches of monkeypox virus (ie, branches ia, ib and iib) spreading at the same time. there is a certain complexity, but in fact it is only local transmission. do we need to panic in china?

jin dongyan:there is no need to panic at all. there is not a single case in china, and there is not a single case in most countries in the world. even if monkeypox type ib is introduced into the united states, according to predictions from the centers for disease control and prevention and related studies, it is unlikely to become a pandemic in the united states and will not cause major damage to the united states. likewise,judging from the transmission characteristics of type ib monkeypox epidemic that we currently know, even if it is introduced into china, it is unlikely to cause great damage to china or cause a large-scale spread.

image source: visual china

2. the current epidemic of monkeypox has far lower mortality and infectivity thansmallpox, there are mature medical methods to deal with it

question: as a close relative of smallpox, how does monkeypox compare in its toxicity and contagiousness? can we still confidently say that "humanity has eliminated smallpox"?

jin dongyan:first of all, smallpox virus and monkeypox virus are both poxviruses.(editor's note: poxviruses are poxviridae, viruses that often cause local or systemic purulent skin lesions after infecting humans and animals. the "pox" in the scientific name comes from english, meaning "pox" or "pustule"), belongs to animal virus. by comparing gene sequences, it is scientifically speculated that smallpox may have originated from animals. although there is currently no very conclusive evidence of virus evolution, the smallpox virus is highly adapted to the human body and only infects humans but not other animals. and centuries later there is still only one type. it is highly contagious and its "r0 value" will be relatively high(editor's note: "r0 value" is the basic infection number, which is a term in epidemiology. it refers to the degree to which a person infected with a certain infectious disease will spread the disease if there is no external intervention and no one is immune. the average number of other people infected. the larger the number of r0, the more difficult it is to control the epidemic),it can be transmitted through the respiratory tract, and droplets are one of the main modes of transmission.

another characteristic of smallpox is that it is highly infectious only when a person has "pox" and has obvious symptoms, and there are basically no asymptomatic spreaders.therefore, through isolation and vaccines, better prevention and control effects can be achieved.

the vaccine for smallpox is a live, attenuated vaccine. because smallpox is a poxvirus, live attenuated vaccines can be used to stimulate the body to produce humoral and cellular immunity, similar to the process of an asymptomatic natural infection.

in 1796, british doctor edward jenner vaccinated james phips against smallpox. source: visual china

has the pox been eradicated? the answer is yes. smallpox and monkeypox are completely different.

smallpox has affected the course of human history to a great extent. many wars at home and abroad, the transfer of imperial power, etc. have been affected by smallpox. but monkeypox does not appear to be the case at present.

first, whether in terms of mortality or infectivity, the two are completely unrelated, differing by several orders of magnitude; second,the "weapons" we have now include vaccinia virus and the mva vaccine currently in use(editor's note: modified ankara vaccinia virus), these vaccines are also very effective against monkeypox. although it is not 100%, it can at least reduce infections by 70 to 80% and prevent monkeypox outbreaks.even if it doesn't completely prevent infection, it can greatly reduce symptoms.if humans can defeat smallpox, there is no reason why they cannot defeat monkeypox.

now, the epidemic in africa has become endemic because it has not been effectively controlled all year round. the democratic republic of the congo is very poor and has been war-torn for years. it is a great regret to say that it does not have an environment for peaceful development and there is no way to effectively control the endemic epidemic of monkeypox.

so to eliminate the problem of monkeypox,it’s not that it can’t be done based on scientific or public health principles., even if the vaccine is effective, people in the democratic republic of the congo are unlikely to be vaccinated, and even if they have "weapons", they will not be able to use it.therefore, everyone should pay attention to the fact that similar situations are not happening now. for example, type ia is more pathogenic and is prevalent in the democratic republic of the congo all year round. in addition, the democratic republic of the congo has no effective measures to prevent it, making it a hotbed of disease. .

the current situation does not mean that humans have no "weapons" to eliminate monkeypox. it does not mean that monkeypox has returned before smallpox has been eliminated. although monkeypox and smallpox belong to the same family, the dangers of monkeypox are not comparable to those of smallpox.

q: if i go to africa now, do i need to get vaccinated?

jin dongyan:our country currently does not provide monkeypox vaccine for everyone to vaccinate. this is a real problem. of course, relevant manufacturers are currently actively developing it.(editor's note: on september 9, the mva strain live attenuated monkeypox vaccine independently developed by sinopharm's china national biotech shanghai institute of biological products received a clinical trial notice issued by the state food and drug administration. this is the first clinical trial approved in my country. monkeypox vaccine)。however, this does not mean that we do not have a vaccine available.

the tiantan strain of vaccinia virus that we used to eliminate smallpox has two vaccines in the united states, one is a replication-deficient vaccine, the mva vaccine, and the tiantan strain of vaccinia virus that is unique to my country and was originally used to prevent smallpox. it has not been re-enabled for now.

as for whether it is necessary to be vaccinated when working or doing business in africa, it is necessary to analyze the specific situation. because there are currently very few countries in africa where monkeypox is endemic,if you go to a relatively high-risk area in the democratic republic of the congo, where monkeypox is shown to be prevalent, and you are likely to come into contact with high-risk people, you can go to hong kong, china or other european and american countries to get vaccinated; on the contrary, go to other african countries where the risk is less the country does not need to vaccinate.

image source: visual china

q: in your opinion, is it necessary for the world to spend a lot of energy and cost on developing a monkeypox vaccine?

jin dongyan:the mva vaccine currently in use around the world is very effective and safe. at the same time, europe and the united states have also approved the use of live attenuated vaccines used in the eradication of smallpox to prevent monkeypox. of our countryvaccinia virus tiantan strain is a live attenuated vaccine that is very effective in preventing monkeypox, but it also has certain side effects.

the country has not yet decided whether we should return to the era when our generation planted the temple of heaven strain, and some experts think it is not necessary, so this is a question of necessity.

the existing vaccines for monkeypox are quite effective. of course, science has no limits, and better vaccines can be made. for example, monkeypox virus type iib is already very weak. to this extent, it can be made weaker until there are no symptoms at all, and a better attenuated vaccine can be made. live vaccines. this is a scientific challenge. whether it is china or the world, it is actually possible to make a vaccine with higher protection, better effect, stronger targeting, and safer. this is what major vaccine manufacturers are considering. there are even some that are already under development, so this can be said to be as it should be.

various vaccine manufacturers used to produce the tiantan strain of vaccinia virus, but now they produce a new mva vaccine, or a new generation of vaccine. scientifically, reserves are needed as a strategy, but reserves are reserves. whether the epidemic of monkeypox will cause a situation similar to smallpox, we have not seen any evidence that there is such a trend or possibility.

there is also the issue of vaccine necessity, whether it is necessary to use it, how to use it most effectively, and how to let the people who need the vaccine most use it, instead of letting everyone get vaccinated, otherwise it may cause a waste. so how can we vaccinate those who really need it and truly reduce the number of monkeypox-infected groups so that they can get the vaccine and afford it? that is an issue that needs to be considered from a public health perspective. there is no need to give it to the whole population now. vaccination.

3. the public needs to be vigilant about monkeypox, but there is no need to worry too much

q: given the current situation, do you think we need to restrict the trade of animals?

jin dongyan:although we call it monkeypox, the world health organization now believes that it should not be called monkeypox, but mpox, that is, mpox. the type ia we just talked about is mainly caused by the contact between humans and animals in forest areas. so what exactly is this animal?everyone speculated that it might be a rodent, but there is no conclusion yet.

there is no need to restrict the trade of animals, especially in the livestock industry, because there is currently no evidence that domestic animals play any role in transmission.in this case, the legal and normal animal trade is not a problem, but it is the illegal trade that needs to be cracked down on. not only monkeypox, but also other wild animals that will be affected, including primates such as various monkeys, rodents, etc. we have strict legal regulations on these since the new crown epidemic. at the same time, other pathogens also need to be strictly controlled, but we cannot stop eating due to choking, and we cannot cancel all other animal trades or strictly control them.

in general, we should protect the legal and crack down on the illegal.

image source: visual china

question: facing the current wave of monkeypox epidemic, what issues do the public need to be particularly vigilant about at the moment, and which issues do not need to be overly worrying?

jin dongyan: no need to worry at all.

regarding the type iib monkeypox that will become popular in 2022, since it is also spread among specific groups, what we need to do is to prevent and treataidsusing the same method as other sexually transmitted diseases, we need to solve and face similar difficulties——they are hidden and outside our monitoring range.and they themselves may avoid seeking medical treatment, etc. these are long-term problems. so we should putaids, monkeypox and other sexually-related infectious diseases, including some bacterial infections, are considered together. it is necessary to clarify how to reach these groups, disseminate correct information to them, and let them move from prevention to treatment and prevention of bacterial viruses. these aspects of communication can be put into practice,this is very important.

everyone needs to understand that the current situation is that in a country with more than 100 million people, monkeypox has been prevalent for many years. it’s just that a new strain has emerged. this strain is different from the strains that were mainly spread in forest areas in the past. it mainly spreads in cities. the scope of spread is a little larger than in the past. the mode of spread has undergone some changes. it is not completely from the virus. animal to human, but very limited human-to-human transmission.

why is it said that it has limited human-to-human transmission? because even in the democratic republic of the congo, its main mode of transmission is limited to close contact and sexual contact. although the monkeypox currently prevalent in africa is more pathogenic than type iib, the mortality rate is less than 1%, or even lower.

image source: visual china

the world health organization has declared it a global public health emergency, which is also to mobilize more resources and use them where they are most needed, using steel on the cutting edge to help resource-deficient countries in africa solve problems.for other countries and regions in the world, its overall threat is still very small. monkeypox will not enter every family or everyone like the new coronavirus.

but how does monkeypox virus change? will a new variant with certain pathogenicity and transmissibility emerge? we have not seen it now, but we need to be more vigilant and strengthen surveillance, especially in africa and some places with virus infections, to strengthen surveillance and related research.therefore, as long as the monitoring is done well, ordinary people do not need to worry about its threat. it has not come to us now, and there is still a certain safe distance from us.

q: from a scientific perspective, what are the core issues that need to be solved to deal with monkeypox?

jin dongyan:there are still many questions, such as what is the real transmission route of type ib? what is the reason for its change in virulence? how does it compare with type ia and type iib? these are some issues that can be ranked as relatively high priority and need to be resolved.

generally speaking, the purpose of strengthening our research on monkeypox is to clarify some basic issues and basic research, including some animal model research and human body research. if we can clarify these issues more clearly, then we will take the next step. response will be more beneficial.

q: will we have to worry about more zoonotic diseases in the future?

jin dongyan:everyone is talking about this issue, including the world health organization’s mention of disease x (editor's note: disease). no one knows what the next time will be, and alarm bells must be ringing.

image source: visual china

we called for many things after sars in 2003: strengthen research, not eat bats, pay attention to wild animals, etc. sixteen years later, in 2019, another similar situation occurred, causing a world pandemic.

nowadays, many people think that the trend has passed and will never happen again, and there is no need to study it anymore. this is definitely wrong. the reason why we are better able to respond to coronavirus infections, especially during this global pandemic, is to do better than in the past. in fact, it has a lot to do with our persistence in working hard to lay a better foundation after 2003. it matters a lot.we still need to increase investment in research on emerging infectious diseases, make more strategic reserves, and build various technology platforms. this is the correct attitude.

as for what viruses, bacteria or other pathogens will be present in the future, there is always uncertainty, and we certainly cannot put all our eggs in one basket. whether it is influenza, bird flu, other coronaviruses or other viruses, new mutant strains of monkeypox, etc., we need to study the potential dangers. the clearer the research, the better we can do in the future.

references:

chinese center for disease control and prevention. monkeypox prevention and control plan.