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Editorials

# Covid-19: breaking the chain of household transmission

BMJ 2020; 370 (Published 14 August 2020) Cite this as: BMJ 2020;370:m3181

## Read our latest coverage of the coronavirus outbreak

1. Shamil Haroon, clinical lecturer in primary care1,
2. Joht Singh Chandan, academic clinical fellow in public health12,
3. John Middleton, president3,
4. Kar Keung Cheng, professor of public health and primary care1
1. 1Institute of Applied Health Research, University of Birmingham, Birmingham, UK
2. 2Warwick Medical School, University of Warwick, Coventry, UK
3. 3Association of Schools of Public Health in the European Region (ASPHER)
1. Correspondence to: S Haroon s.haroon{at}bham.ac.uk

The UK is one of the countries most severely affected by covid-19. Recent outbreaks in English towns such as Oldham, probably involving transmission within large multigenerational households, show the importance of getting the right public health measures in place now to prevent more widespread surges in infections.1

Current test and trace policies have mainly focused on preventing spread in care homes, hospitals, and in the community.2 However, contact within households is thought to be responsible for roughly 70% of SARS-CoV-2 transmission when widespread community control measures are in place.3 In Wuhan, the reproduction number (R) dropped from 3.54 to 1.18 after lockdown and cordon sanitaire. But the epidemic was only brought under complete control when Fangcang (field) hospitals were introduced to isolate cases outside the home, with R dropping to 0.51 after two weeks.4

Current UK guidance advises household contacts to isolate within the same home as the index case for 14 days.5 They make up the majority of contacts for infected individuals and are likely to remain exposed to the infected household member during this period of isolation.6 Despite guidance advising household members to socially distance, contacts are likely to interact repeatedly—during mealtimes, for example—and to share facilities such as bathrooms.

We know that transmission is more likely to occur indoors than outdoors.7 The cumulative risk to household contacts from an infected person is likely to be substantial during peak viral shedding. In one study in New York State, 38% of household contacts tested positive for SARS-Cov-2, and similar secondary infection rates have been reported in China.89 Transmission may be even higher among household contacts of essential workers, who are at greater risk of being infected than the general population.10

Household members who are older, have underlying medical conditions, or share a bed or vehicle with the index case are the most susceptible.91112 Children seem to be at lower risk of being infected.13 However, their stool samples and nasopharyngeal swabs can remain positive for SARS-CoV-2 for more than two weeks after symptom resolution,14 although their role in transmission remains to be established.

Governments should consider new public health measures to prevent household transmission as we prepare for a potential second wave. Household quarantine is likely to remain an important pandemic control measure, and government support for people quarantined at home is conspicuously absent in the UK: this position has been challenged by independent experts.15

## Effective isolation

Effective isolation of index cases from household members could reduce secondary infections.12 Wearing masks within quarantined households may help, particularly if used by the index case as soon as infection is suspected.16 The World Health Organization recommends that infected people and unavoidable close contacts, particularly those in vulnerable groups, should wear medical masks, but Public Health England does not currently recommend this. Other measures that should be considered (and evaluated) include clear advice on enhanced personal hygiene; cleaning and disinfecting shared toilets and other common spaces, door handles, and touch points; and staggering mealtimes.

People who are unable to self-isolate safely at home could be accommodated in special isolation facilities such as hotels and hostels, an approach adopted by some other countries, including Italy, Finland, and Lithuania.17 In China, field hospitals were created to manage and strictly isolate patients with mild-to-moderate covid-19.18 Nightingale hospitals in the UK could be similarly repurposed to support isolation of infected people with mild-to-moderate disease. As medical and nursing care needs are mostly modest, the cost would be relatively low. However, such a system depends on access to rapid testing for anyone with symptoms or possible exposure so that infection can be confirmed and isolation started before transmission occurs. It would also require public trust that isolation in these facilities would be voluntary, safe, and supportive.

“Obviously, a single year, even if it is a record, cannot tell us much about climate trends,” said Stefan Rahmstorf, head of earth system analysis at the Potsdam Institute for Climate Impact Research in Germany. “However, the fact that the warmest years on record are 2014, 2010 and 2005 clearly indicates that global warming has not ‘stopped in 1998,’ as some like to falsely claim.”
Typically, he writes, analysts “see the root cause of emerging markets’ susceptibility to crises in weak institutions that make countries vulnerable to economic and financial instability.”
Tiemba scores highly forinternational experience, being delivered half on Tsinghua’s campus in Beijing as well as on Insead’s three campuses in Singapore, France and the UAE.

“That’s the difference between tweeting from your couch and governing the country. If you govern the country, you have to take sensible decisions, and that isn’t sensible,” Mr Rutte replied.
She’s No. 1: Chancellor Merkel has made the list eight times out of the past ten years — seven times as No. 1.

es to you and yours.以我所有的爱心与真诚祝你及全家圣诞快乐。
But we at The BostonConsulting Group believe that the current dip in China’s growth will not endureand that, under Xi’s leadership, China’s economy is destined to continuegrowing at a rapid clip. In fact, we are confident last week’s reforms willcontribute mightily to China’s growth between now and 2020. We stand by our base case forecast that China will deliver$4 trillion in growth over the next decade and combine with India to deliver a$10 trillion prize — an economic powerhouse driven by booming middle classconsumption and growing overall optimism. No one can perfectly forecastthe future … and in our book we describe scenarios where growthslows. But we remain optimistic and positive about China’s future.
n. 舒适，安逸，安慰，慰藉
Premiered in August, the 48-episode TV series is a fictional story, with a plot centering on struggles and romance during the Qin Dynasty (221-206 BC).

## Footnotes

• 五大要点读懂《关于推进养老服务发展的意见》
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Rank: 5
Sohmers所推出的这个产品，可谓将高速运算能力和低能耗集为一体。Sohmers表示：“除了电子工程师外，我认为我还是一位创业者。我相信，我所作的工作，将会对整个世界产生重要的影响。”Sohmers在几年前从高中辍学，加入了Peter Thiel创立的创业加速器20 Under 20 Thiel Fellowship。2011年，在其他同龄人都在准备考大学的时候，Sohmers开始学习编程。他获得了10万美元的种子资金，并且跟随硅谷中一些著名的技术人才进行学习。Sohmers曾在麻省理工学院研究实验室进行工作和学习，研究从增强现实眼镜到激光通信系统的任何东西。也是在那里，他见到了REX的另一位联合创始人Kurt Keville。但是在他正式进入麻省理工学院研究室之前，他的父母似乎并不太支持他放弃学业。

7.Yes, John was with me last night. – Because that’s what friends do… we agree and ask questions later。

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