Pre-symptomatic asymptomatic MonkEypox (PRIME) study

猴痘（MPX）是由猴痘病毒引起的病毒性感染，以前主要局限于西非和中非，偶尔因国际旅行而感染。2022年之前的大多数病例可能是因为人们遇到了感染病毒的动物，可能是啮齿动物，但也可能是生活在西非和中非的许多动物。然而，自2022年5月以来，世界各地爆发了大规模疫情，主要影响同性恋、双性恋和其他男男性行为者（GBMSM）。截至2022年8月底，英国确诊病例超过3200例。已经出现了持续的人际传播，表明感染是在人与人之间传播，而不是需要人与受感染的动物接触。猴痘主要通过密切接触传播，可能通过暴露于感染者的皮肤损伤（斑点）或最近被污染的床单。先前的猴痘感染看起来很像天花或水痘，全身都有病变（或凸起的斑点，可以变成充满液体的水泡）。在2022年的新疫情中，人们被诊断出的斑点要少得多，向性健康服务机构提出的腹股沟区域斑点有限，或者可能无法诊断的小溃疡。目前尚不清楚在出现任何症状和出现斑点之前，人们感染猴痘的频率，或者实际上，人们在不知道自己感染了猴痘（无症状感染）的情况下可能具有传染性。这对我们理解不同控制措施的效果至关重要。如果人们没有明显的斑点或症状而没有传染性，他们将能够被告知需要注意哪些症状，这意味着他们应该寻求医疗救助，特别是如果他们与猴痘感染者（一个病例）有过密切接触。如果许多人可能在不知情的情况下具有传染性，这将严重限制消息传递的影响，即了解症状以控制任何疫情。只有通过使用高效疫苗实现人口水平的疫苗接种覆盖率，或通过行为上的重大改变，才能实现控制。来自天花（一种相关病毒）和此前在西非进行的抗体研究的一些证据表明，居住在已知存在猴痘地区的人可能出现无症状感染（或感染未被识别的轻微症状）疾病。猴子也可以在没有症状的情况下被感染。从目前的疫情来看，法国和比利时性健康诊所的早期研究表明，一些人可能在没有症状的情况下被感染，或者在症状出现之前就已经被检测到感染。少数病例也有初步迹象表明，传播可能发生在感染早期，这可能包括在个人发现自己有症状之前。然而，迄今为止还没有研究对猴痘病例的一组接触者进行调查，以详细确定a)这种情况有多普遍b)人们可能感染多久。我们将尝试回答这些问题，方法是询问通过公共卫生接触者追踪或通过在线社交媒体招聘的自我推荐确定的猴痘病例的密切性接触者，以采集拭子和尿液样本，并进行血液检查以寻找抗体，并回答有关症状和猴痘暴露的在线问卷。我们还将能够汇编这些数据，以估计有多少接触者继续发展为猴痘感染，以及对那些接种过疫苗的人来说，疫苗的有效性如何。该研究将通过UKHSA实验室团队、现场流行病学、免疫、数据处理和统计专家、参与国家事件应对的相关团队、性健康同行专家和性健康研究学者之间的合作进行。

Monkeypox (MPX) is a viral infection caused by monkeypox virus, previously largely confined to West and Central Africa, with occasional infections arising from international travel. Most cases before 2022 are likely due to people encountering animals who are infected with the virus, likely a rodent but possible many animals that live in West and Central Africa. However, since May 2022 there has been a large outbreak all over the world, largely affected gay, bisexual and other men who have sex with men (GBMSM). By the end of August 2022, over 3,200 cases had been diagnosed in the UK. There has been sustained human-to-human transmission, showing that infection is spreading from person to person rather than needing people to encounter an infected animal. Monkeypox is predominantly spread from close contact, likely from exposure to skin lesions (spots) or recently contaminated bedsheets of an infected person.The previous monkeypox infection looks a lot like smallpox, or chickenpox, with lesions (or raised spots which can turn into blisters filled with fluid) all over the body. In this new 2022 outbreak, people have been diagnosed with far fewer spots, presenting to sexual health services with limited spots in the groin region, or small ulcers that may go undiagnosed.It is not known how often people may be infectious before the onset of any symptoms and development of spots, or indeed inf people can be infectious without ever knowing they have monkeypox infection (asymptomatic infection). This is vital to our understanding of how well different control measures will work. If people are not infectious without obvious spots or symptoms, they will be able to be told what symptoms to look out for that means they should seek medical attention, particularly if they have been in close contact with someone who has had monkeypox infection (a case). If many people can be infectious without knowing it, this will severely limit the impact of messaging to be aware of symptoms to control any outbreak. Control will only be possible by achieving population level vaccination coverage with a highly effective vaccine, or by considerable change in behaviour. There is some previous evidence from smallpox, a related virus, and from prior antibody studies in West Africa that have shown likely asymptomatic infection (or infection with unrecognised minor symptoms) disease in people who live in areas where monkeypox is known to exist. Monkeys are also known to be able to be infected without symptoms. From the current outbreak, early research in sexual health clinics in France and Belgium has shown that several people can likely be infected without ever displaying symptoms or have detectable infection before symptoms develop. There are also preliminary indications from a small number of cases that transmission may be occurring early in infection, which may include before individuals have identified that they are symptomatic. However there is no study to date that looks at a group of contacts of monkeypox cases to determine in detail a) how common this is b) how long people may be infectious for. We will attempt to answer these questions by asking close sexual contacts of monkeypox cases who have either been identified from public health contact tracing or from self-referral from online social media recruitment to take swabs and urine samples, along with blood tests to look for antibodies, and answer an online questionnaire about symptoms and monkeypox exposure. We will also be able to compile these data to also get an estimate of how many contacts go on to develop monkeypox infection and for those who have been vaccinated, how effective the vaccine is.The study will be conducted through collaboration between laboratory teams at UKHSA, field epidemiology, immunisation, data processing, and statistical experts, relevant teams engaged in national incident response, sexual health peer experts, and academics in sexual health research.