猴痘的未來會是什麼樣子？
隨著美國和歐洲病例的減少，《自然》雜誌研究了疫情可能如何發展的情景。
資料來源：Sara Reardon / 新聞特寫 / 2022 年 10 月 12 日 / 自然 / 財團法人台灣紅絲帶基金會編譯
加拿大多倫多的猴痘公共衛生標誌。圖片來源：：史蒂夫·拉塞爾/多倫多之星/蓋蒂
4 月 29 日，奈及利亞的一個人出現了一種不尋常的皮疹，然後帶著猴痘前往英國。從那時起，該病毒已傳播到 100 多個國家/地區的 70,000 多人。這讓世界各地的醫療保健專家感到驚訝，因為這種持續的傳播與之前在人類中爆發的由一種生活在非洲動物體內的病毒引起的猴痘爆發不同。
然而，在病毒開始傳播近六個月後，疫苗接種工作和行為改變似乎遏制了當前的毒株——至少在美國和歐洲是這樣（參見「猴痘病例」）。但研究人員表示，這種情況仍可能以多種方式出現。充其量，疫情可能會在接下來的幾個月或幾年內消失。在最壞的情況下，該病毒可能會透過到達新的動物宿主而在非洲以外地區流行，幾乎不可能根除。紐約市哥倫比亞大學的傳染病醫生傑西卡·賈斯曼 (Jessica Justman) 說：「正有很多因素在朝著相反的方向起作用」。
資料來源：世界衛生組織
全球猴痘通報病例曾在歐洲及美國於八月達到最高峰，但在該等地區病例數已於高峰後逐漸減少
專家們預計，今年的疫情不會造成像 COVID-19 那樣的全球性破壞。猴痘病毒似乎不像 COVID-19 那樣通過空氣傳播，不像天花那樣具有高度傳播性，也不像 HIV 那樣在體內持久存在。它主要透過性接觸傳播，主要在男男性行為者中被診斷出來，特別是那些有多個性伴侶或有匿名性行為的人。儘管它會引起嚴重、疼痛的皮疹，但很少致命。此次疫情是西非較溫和的進化枝2 (clade 2) 猴痘病毒的後裔。 （在中非發現了一種更致命的「進化枝 1」病毒。）目前尚不清楚導致當前爆發的毒株在本質上是否比它的進化枝 2 祖先更具有傳播性。阿拉巴馬大學伯明翰分校的生物信息學家 Elliot Lefkowitz 說，更進一步說，這種病毒的一種形式可能已經傳播到人群中，這些人群的行為導致其傳播得更快。
亞特蘭大喬治亞州立大學的流行病學家 Gerardo Chowell-Puente 說：「我認為我們處於控制這種流行病的有利位置，但這主要取決於人們的行為」。
由於對最新的猴痘病毒株的了解是如此之有限，而且可能發生的狀況很大程度上取決於人們的反應，因此很難預測未來的趨勢。儘管如此，研究人員已經制定了一些情景來幫助規劃疫情可能發展的不同方式。以下是關於猴痘未來的一些重大問題。
目前的趨勢是什麼？
在美國和歐洲，自 8 月中旬以來，已確認的猴痘感染病例一直在下降。
公共衛生專家讚揚行為改變：美國疾病控制和預防中心 (CDC) 對男男性行為者進行的一項調查發現，由於擔心病毒，大約一半的人一直在遏制危險的性活動。可能也有幫助的還有公共衛生運動，這些運動告訴人們要尋找什麼症狀並鼓勵他們報告病例，以及向高危人群提供的疫苗（儘管疫苗在減少感染或傳播方面的功效尚不清楚）。
猴痘病毒正在變異。科學家們擔心嗎？
不過，賈斯曼說，猴痘病例數有嚴重的應注意事項。許多人——以及他們的醫生——可能沒有意識到這些症狀，或者可能因為恥辱而害怕報告其感染。「我不相信所有需要接受檢測的人都在接受檢測」，她說。
而南美洲和非洲的一些國家則看到了相反的趨勢。「現在說我們已經打敗了它還為時過早」，奈及利亞威爾伯福斯島奈及爾三角洲大學的傳染病醫生 Dimie Ogoina 說。這個國家當前的疫情可能已經開始，病例繼續上升，9 月份報告的每週記錄為 56 例。位於阿布賈的奈及利亞疾病控制中心表示，該國已出現 400 多例病例。與美國的 26,000 例病例相比，這是一個很小的數字，但幾乎可以肯定是大大地低估了； Ogoina 說，奈及利亞錯過的人數可能比美國多得多。奈及利亞沒有強大的疾病監測計畫，奧戈伊納預計，許多感染該病毒的人可能無法識別症狀或去看醫生。瑞士日內瓦世界衛生組織 (WHO) 猴痘技術負責人 Rosamund Lewis 表示，報告的病例數總是被低估，特別是在沒有良好監測計劃的地區。
世衛組織希望獲得 60,000 套檢測試劑盒運往非洲，但讓人們接受檢測和診斷是一項後勤挑戰。劉易斯說，目前還不清楚非洲病例的明顯上升是否反映了那裡真正的爆發，或者是更徹底檢測的結果。她懷疑這兩個因素都有影響。
模型投射些什麼？
由於對猴痘如何傳播以及不同因素如何影響這一點知之甚少，因此提前幾周建模不太可能產生準確的結果。世界衛生組織沒有發布長期猴痘預測。儘管 CDC 每月發布一份關於疫情的技術報告，其中包含一系列潛在情況，但該機構表示，它對其預測只有中等信心。其 9 月 29 日的最新報告稱，美國病例最有可能在下個月趨於平穩或下降，但也有可能呈指數級增長（參見go.nature.com/3sxrbmv）。
猴痘有多致命？科學家知道些什麼
Chowell-Puente 在網上發布每週猴痘預測，並跟踪美國和歐洲幾個國家的趨勢。他使用了幾種情景來生成一個整體的三週預測，該預測迄今為止相當準確地反映了實際趨勢。截至 10 月 3 日，他預測他所模擬的國家的病例將趨於平穩或下降。 Chowell-Puente 說，儘管如果有新的公共衛生政策、公眾行為的改變或病毒的突變，這些趨勢可能會改變，但它們不太可能很快改變。他還沒有為非洲的案例建模，但表示他將來可能會這樣做。
其他模型更詳細，但不一定更準確。 RTI International（一家非營利性全球研究機構，總部位於北卡羅來納州三角研究園）的研究人員提供使用了來自猴痘病毒先前爆發的一個系統（特別是進化枝 2 爆發）的信息來預測當前可能發生拉緊的情況。值得注意的第 2 支進化枝之前的爆發包括 2003 年在美國發生的一次短暫的爆發，感染了 70 多人，以及 2017 年在奈及利亞發現並導致 146 例疑似病例的爆發。從病毒基因組的分析來看，這似乎是導致目前情況的毒株。
英國諾丁漢的 RTI 流行病學家 Donal Bisanzio 使用來自這些爆發的信息並假設病毒沒有顯著變異，估計了病毒的傳播性。他和他的團隊模擬了病毒如何在數週內在一個擁有 5,000 萬人口的高收入國家傳播。在尚未發表的工作中，該模型預測，如果這個虛擬國家不採取任何措施來對抗病毒，那麼在疫情消退之前，預計會出現大約 6,000 例病例（即感染 0.01% 的人
口）。這主要是因為該病毒的傳播性不強，而且該模型假設（如美國等國家的情況）大多數老年人已接種過天花疫苗，這是一種相關病毒。
但研究人員發現，如果感染者將自己隔離三週（等待猴痘可能的潛伏期），並且如果男男性行為者在疫情結束前控制性行為，感染人數將顯著下降。為感染者的接觸者接種疫苗可以進一步減少感染。
疫苗接種不會平息疫情嗎？
歐洲和美國已經分發了數十萬劑疫苗，以幫助為高危人群接種疫苗，例如男男性行為者和與病毒接觸者接觸過的人。為所有人接種疫苗不是一種選擇：美國預計今年將提供不到 200 萬劑最廣泛使用的疫苗——一種重新利用的天花疫苗。
為什麼科學家擔心猴痘會在野生動物中傳播
但目前尚不清楚這會在多大程度上導致病例數下降。例如，一份預印本顯示，在從未接種過天花疫苗的人群中，該疫苗似乎不會大大提高可以中和猴痘病毒的抗體追加水平，而這些抗體是免疫反應的一個組成部分。相比之下，美國疾病控制與預防中心發布的粗略病例率數據顯示，在建議接種疫苗的人群中，未接種疫苗的人的猴痘發生率比接種疫苗的人高十倍以上（見 go.nature.com/3yifurf ）。 （然而，這些數據並未針對年齡、潛在狀況、行為或兩組之間的其他差異進行控制）。幾項測試疫苗有效性的臨床試驗正在進行中。
目前還不清楚疫苗的效果會持續多久。在一篇未發表的論文中，Ogoina 報告說發現一名未接種疫苗的人在從最初的感染中恢復後僅 9 個月就被再次感染，這顯示免疫力下降的速度可能比科學家預期的要快。
但專家們並不認為疫苗會變得毫無用處。 Lefkowitz 說，天花疫苗是在疾病被根除之前大約 180 年發明的，但在那個時候，引起天花的天花病毒——猴痘病毒的近親——從未進化出抵抗接種的能力。儘管目前還沒有批准的治療猴痘的方法，但目前正在測試一些用於天花的抗病毒藥物對猴痘的療效。
什麼可能導致病例增加？
美國和歐洲的趨勢令人鼓舞，但如果人們感覺到危險已經過去，賈斯曼說，危險行為的增加可能會導致病毒捲土重來。她特別擔心病毒在大學校園內傳播的可能性，因為學生們住在近距離，可能會進行涉及長時間身體接觸的運動。「我認為事情不會停滯不前」，她說。「它們會進化，我們的指引也會進化」。
Dimie Ogoina 醫生在奈及利亞工作，那裡的猴痘病例正在上升。
圖片來源：KC Nwakalor/The New York Times/Redux/eyevine
與此同時，在奈及利亞，Ogoina 擔心這種病毒可能會在 HIV 陽性人群中迅速傳播——僅在奈及利亞就有近 200 萬人。儘管證據很少，但 2017 年那裡爆發的記錄顯示，猴痘在這些人中的致命性要高得多，這些人的免疫系統通常較弱。
如果病毒變異了怎麼辦？
與 SARS-CoV-2 或 HIV 等 RNA 病毒不同，猴痘病毒的基因組由 DNA 組成，由於它更穩定，因此比 RNA 產生突變的速度更慢。 《自然醫學》雜誌 6 月份的一篇論文報告稱，在歐洲傳播的病毒比以前的痘病毒更快地發現單字母之突變，這讓研究人員感到驚訝。但這些突變似乎收效甚微；研究人員說，它們可能是人類抗病毒酶在試圖使病毒失活上裁剪的標誌。科學家們還在一些猴痘基因組中發現了缺失或重排的區域。這些在痘病毒中很常見，並且尚未與功能變化有關。
猴痘：大學如何預防校園爆發
萊夫科維茨和其他人說，很難估計這種病毒在未來變得更具傳染性的可能性，儘管不能排除這種可能性。對由人類酶活性引起的猴痘 DNA 突變的一項分析（尚未經過同行評審）推斷，當前的毒株可能在 2016 年首次感染人類，然後於 2017 年在奈及利亞發現疫情（見 go.nature.com/ 3 ）。但研究人員不知道該病毒是否自那時以來一直在人類之間持續傳播而未被發現，或者它是否在最近幾年又回到動物體內，然後又回到人類體內，這可能是由於某種特定突變的幫助。萊夫科維茨說：「目前的病毒中沒有一種特殊的突變是確鑿的證據」，萊夫科維茨說，就針對使人們患病或更容易傳播感染而言。
「我們對傳播的理解並不比我們對病原體的理解更好」，他補充道。他說，儘管如此，爆發持續的時間越長，出現令人擔憂的突變的機會也會增加。
如果病毒找到新的宿主怎麼辦？
研究人員仍然不知道非洲的哪種動物是最重要的猴痘宿主，攜帶病毒並將其傳播給人類。囓齒動物是可能的候選動物：2003 年美國爆發時，從加納進口的囓齒動物感染了寵物草原土撥鼠。但這種病毒也在許多其他哺乳動物中發現，包括猴子和食蟻獸。
8 月，研究人員在法國發現了一隻狗，它從主人那裡感染了這種病毒，但目前尚不清楚該動物是否會將病毒傳回給人類。美國疾病預防控制中心更新了其指南，以阻止患有猴痘的人與動物互動。但 Chowell-Puente 認為猴痘不太可能在非洲以外的動物中找到永久的家園，因為這種病毒需要時間來適應新物種並傳播。目前的菌株似乎更喜歡人類。
完全消除猴痘需要什麼？
在發生動物傳人的地區，如果沒有針對人和（最終）動物的疫苗，就不可能完全消除病毒。然而，儘管病毒可能會再次從非洲傳播出去，但奧戈伊納說，非洲國家尚未接種任何疫苗。那是因為富裕國家還沒有向無力負擔的國家捐贈任何劑量。
奈及利亞疾病控制中心駐倫敦的流行病學家 Adesola Yinka-Ogunleye 表示，即使疫苗真的問世，也需要改變行為來遏制猴痘，尤其是考慮到有關疫苗有效性的懸而未決的問題。「如果我們不在流行地區控制猴痘，那麼無論在非流行國家付出什麼努力，我們都知道我們不會實現控制」，她說。
《自然 》610, 250-252 (2022); doi：https://doi.org/10.1038/d41586-022-03204-7
參考文獻：Delaney, K. P. et al. MMWR Morb. Mortal. Wkly Rep.《發病率及死亡率週報》71, 1126–1130 (2022)。
What does the future look like for monkeypox?
With cases declining in the United States and Europe, Nature examines scenarios of how the outbreak might play out.
Sara Reardon / NEWS FEATURE / 12 October 2022 / Nature
A public-health sign about monkeypox in Toronto, Canada. Credit: Steve Russell/Toronto Star/Getty
On 29 April, a person in Nigeria developed an unusual rash and then travelled to the United Kingdom —carrying monkeypox with them. Since then, the virus has reached more than 70,000 people in over 100 countries. That has surprised health-care specialists around the world, because the sustained spread doesn’t resemble the sporadic pattern of previous monkeypox outbreaks in people, caused by a virus that lives in animals in Africa.
Almost six months after the virus started to spread, however, vaccination efforts and behavioural changes seem to be containing the current strain — at least in the United States and Europe (see ‘Monkeypox cases’). But the situation could still play out in several ways, say researchers. At best, the outbreak might fizzle out over the next few months or years. At worst, the virus could become endemic outside Africa by reaching new animal reservoirs, making it nearly impossible to eradicate. “There are so many factors at play that are working in opposing directions,” says Jessica Justman, an infectious-disease physician at Columbia University in New York City.
Source: WHO
Specialists don’t expect that this year’s outbreak will cause the kind of worldwide disruption seen with COVID-19. The monkeypox virus doesn’t seem to be airborne like COVID-19, highly transmissible like smallpox or long-lasting in the body like HIV. It spreads mostly through sexual contact, and has been diagnosed mainly in men who have sex with men, particularly those with multiple sexual partners or who have anonymous sex. And although it causes severe, painful rashes, it is rarely fatal; the outbreak is a strain descended from the milder ‘clade 2’ monkeypox virus in West Africa. (A more deadly ‘clade 1’ virus is found in Central Africa.) It is not clear that the strain causing the current outbreak is any more intrinsically transmissible than its clade 2 ancestors; rather, a form of the virus could have reached a population whose behaviours led it to spread more rapidly, says Elliot Lefkowitz, a bioinformatician at the University of Alabama at Birmingham.
“I think we are in a good position to control this epidemic, but it will mostly rely on the behaviour of the population,” says Gerardo Chowell-Puente, an epidemiologist at Georgia State University in Atlanta.
With so much unknown about the latest monkeypox strain and so much contingent on how people respond, it is difficult to predict future trends. Still, researchers have developed scenarios to help plan for the different ways the outbreak might progress. Here are some of the big questions about monkeypox’s future.
What are the current trends?
In the United States and Europe, confirmed monkeypox infections have been declining since mid-August.
Public-health experts credit behavioural change: a study1 by the US Centers for Disease Control and Prevention (CDC) that surveyed men who have sex with men found that around half had been curbing risky sexual activity because of concerns about the virus. Also probably helpful were public-health campaigns that told people what symptoms to look for and encouraged them to report cases, as well as vaccines that were offered to people at high risk (although the vaccines’ efficacy at reducing infection or spread is unclear).
The monkeypox virus is mutating. Are scientists worried?
Still, the monkeypox case numbers have serious caveats, Justman says. Many people — and their physicians — probably do not recognize the symptoms or might be afraid to report an infection because of the stigma. “I have no confidence that all the people who need to be tested are being tested,” she says.
And some countries in South America and Africa are seeing the opposite trend. “It’s too early to say we have defeated it,” says infectious-disease physician Dimie Ogoina at Niger Delta University in Wilberforce Island, Nigeria. In that country, where the current outbreak is likely to have started, cases continue to rise, with a weekly record of 56 reported in September. The Nigeria Centre for Disease Control in Abuja says the country has seen more than 400 cases. That is a small number compared with the United States’ 26,000 cases, but is almost certainly a vast undercount; it is likely that many more are being missed in Nigeria than in the United States, Ogoina says. Nigeria does not have a strong disease-surveillance programme, and Ogoina expects that many people who catch the virus might not recognize the symptoms or go to physicians. Reported case numbers will always be undercounts, especially in areas that don’t have good surveillance programmes, agrees Rosamund Lewis, technical lead for monkeypox at the World Health Organization (WHO) in Geneva, Switzerland.
The WHO hopes to acquire 60,000 test kits to ship to Africa, but it is a logistical challenge to get people tested and diagnosed. It is also unclear whether the apparent rise in African cases reflects a true outbreak there or is the result of more thorough testing, Lewis says. She suspects that both factors contribute.
What do models project?
Because so little is known about how monkeypox spreads and how different factors could affect that, modelling more than a few weeks in advance is unlikely to produce an accurate result. The WHO does not release long-term monkeypox forecasts. And although the CDC releases a monthly technical report on the outbreak with a set of potential scenarios, the agency says it has only moderate confidence in its predictions. Its latest report, on 29 September, said that US cases are most likely to plateau or fall over the next month, but it is also possible they could increase exponentially (see go.nature.com/3sxrbmv).
How deadly is monkeypox? What scientists know
Chowell-Puente releases a weekly monkeypox forecast online, and follows trends in the United States and several countries in Europe. He uses several scenarios to produce an overall three-week forecast that has reflected real trends fairly accurately so far. As of 3 October, his forecast predicts that cases will either plateau or decline in the countries he models. Chowell-Puente says that although these trends could change if there is a new public-health policy, an alteration in the public’s behaviour or a mutation in the virus, they are unlikely to do so quickly. He hasn’t modelled cases in Africa, but says he might in the future.
Other models are more detailed, although not necessarily more accurate. One system, from researchers at RTI International (a non-profit global research institute headquartered in Research Triangle Park, North Carolina), used information from previous outbreaks of the monkeypox virus — specifically the clade 2 outbreaks — to project what could happen with the current strain. Previous notable clade 2 outbreaks include a short-lived one in the United States in 2003, which infected more than 70 people, and an outbreak in Nigeria that was spotted in 2017 and led to 146 suspected cases. From analyses of viral genomes, this seems to be the strain that led to the current situation.
Using information from those outbreaks — and assuming that the virus has not significantly mutated — Donal Bisanzio, an RTI epidemiologist who is based in Nottingham, UK, estimated viral transmissibility. He and his team modelled how the virus would spread over the course of weeks in a virtual high-income country of 50 million people. In as-yet-unpublished work, the model predicts that if the virtual country did nothing to combat the virus, it could expect around 6,000 cases (that is, infecting 0.01% of the population) before the outbreak fizzled out. This is largely because the virus is not very transmissible and because the model assumes (as is the case in countries such as the United States) that most older people have been vaccinated against smallpox, a related virus.
But the researchers found that the number of infections would drop significantly if infected people isolated themselves for three weeks (to wait out monkeypox’s possible incubation period), and if men who have sex with men curbed their sexual activity until the end of the outbreak. Vaccinating an infected person’s contacts could reduce infections slightly further.
Wouldn’t vaccination quash the outbreak?
Hundreds of thousands of doses have been distributed in Europe and the United States to help vaccinate people at high risk, such as men who have sex with men and people who have been in contact with someone exposed to the virus. Vaccinating everyone isn’t an option: the United States anticipates that fewer than two million doses of the most widely used vaccine — a repurposed smallpox jab — will be available this year.
Why scientists fear monkeypox spreading in wild animals
But it is unclear how much this has contributed to the slowdown in case numbers. One preprint, for instance, has suggested that, in people who have never had a smallpox inoculation, the vaccine does not seem to greatly boost levels of antibodies that can neutralize the monkeypox virus, and which are one component of an immune response. By contrast, the CDC has released crude case-rate data from US jurisdictions suggesting that monkeypox incidence — among those people recommended to receive the vaccine — has been more than ten times higher among unvaccinated than vaccinated individuals (see go.nature.com/3yifurf). (These data, however, were not controlled for age, underlying conditions, behaviour or other differences between the two groups). Several clinical trials testing vaccine effectiveness are under way.
It is also unclear how long vaccine effects will last. In an unpublished paper, Ogoina reports finding one unvaccinated person who was reinfected just nine months after recovering from his initial infection, suggesting that immunity might wane more quickly than scientists had anticipated.
But specialists don’t expect that the vaccine will become useless. The smallpox vaccine was invented some 180 years before the disease was eradicated, but in that time, the variola virus that causes smallpox — a relative of the monkeypox virus — never evolved to resist the jab, Lefkowitz says. And although there are no currently approved treatments for monkeypox, a few antiviral drugs used for smallpox are currently being tested for their efficacy against monkeypox.
What could cause cases to increase?
The US and European trends are encouraging, but if people sense that the danger has passed, Justman says, an increase in risky behaviour might cause a resurgence of the virus. She is particularly concerned about the virus’s potential to spread on university campuses, where students live in close quarters and might play sports that involve extended physical contact. “I don’t think things will stand still,” she says. “They will evolve, and our guidance will evolve.”
Physician Dimie Ogoina works in Nigeria, where monkeypox cases are rising.Credit: KC Nwakalor/The New York Times/Redux/eyevine
In Nigeria, meanwhile, Ogoina is concerned that the virus could spread quickly among people who are HIV-positive — nearly two million people in Nigeria alone. Although evidence is scarce, records from the 2017 outbreak there suggest that monkeypox is much more deadly in many of these individuals, who often have weakened immune systems.
What if the virus mutates?
Unlike RNA viruses such as SARS-CoV-2 or HIV, the monkeypox virus’s genome is composed of DNA, which tends to accrue mutations more slowly than RNA because it is more stable. A June paper in Nature Medicine surprised researchers when it reported that the virus that was spreading through Europe had picked up single-letter mutations much faster than previous poxviruses had. But these mutations seem to have had little effect; they are probably markers of where human antiviral enzymes have snipped at the virus in attempts to deactivate it, the researchers said. Scientists have also found areas of deletions or rearrangements in some monkeypox genomes; these are common in poxviruses and haven’t yet been linked to a change in function.
Monkeypox: how universities are preventing outbreaks on campus
It is difficult to estimate the chances of the virus becoming more transmissible in the future, Lefkowitz and others say, although that can’t be ruled out. One analysis (not yet peer reviewed) of the mutations in monkeypox DNA caused by human enzyme activity has inferred that the current strain might have first reached humans in 2016, before the outbreak was identified in Nigeria in 2017 (see go.nature.com). But researchers don’t know whether the virus has been continuously transmitting between humans undetected since then, or whether it hopped back into animals for a few years before crossing back into humans more recently, perhaps aided by a particular mutation. “There’s no one particular mutation in the current virus that is a smoking gun,” Lefkowitz says, in terms of making people more ill or more likely to spread the infection.
“We don’t understand transmission any better than we understand the pathogen,” he adds. Still, he says, the chance of a worrisome mutation arising increases the longer the outbreak goes on.
What if the virus finds a new reservoir?
Researchers still don’t know what animal in Africa serves as the most important monkeypox reservoir, carrying the virus and spreading it to humans. Rodents are a likely candidate: the 2003 US outbreak happened when rodents imported from Ghana infected pet prairie dogs. But the virus has also been found in numerous other mammals, including monkeys and anteaters.
In August, researchers found a dog in France that had contracted the virus from its owners, although it is unclear whether the animal could transmit it back to humans. The US CDC updated its guidance to discourage people with monkeypox from interacting with animals. But Chowell-Puente thinks it’s unlikely that monkeypox will find a permanent home among animals outside Africa, because the virus requires time to adapt to a new species and transmit. The current strain seems to prefer humans.
What would it take to eliminate monkeypox altogether?
In areas where animal-to-human transmission occurs, it will be impossible to eliminate the virus completely without a vaccine for people and (eventually) animals. Yet despite the risk that the virus might spread out of Africa again, Ogoina says that African countries have not yet received any vaccines. That’s because wealthy nations have not yet donated any doses to countries that cannot afford them.
Even if vaccines do arrive, behavioural changes will be needed to curb monkeypox, especially given the unanswered questions about vaccine effectiveness, says Adesola Yinka-Ogunleye, a London-based epidemiologist at the Nigeria Centre for Disease Control. “If we do not control monkeypox in endemic areas, then no matter the efforts put into non-endemic countries, we know we’re not going to achieve control,” she says.
Nature 610, 250-252 (2022)
doi: https://doi.org/10.1038/d41586-022-03204-7
References
Delaney, K. P. et al. MMWR Morb. Mortal. Wkly Rep. 71, 1126–1130 (2022).