Sarah Chapman looks at a Cochrane Rapid Review, published yesterday, with evidence from mathematical modelling studies on the The ability of an intervention (for example a drug, surgery, or exercise) to produce a desired effect, such as reduce symptoms. of quarantine for controlling the spread of COVID-19 (coronavirus).
Last month I blogged about two rapid reviews by researchers at King’s College London on what makes people more likely to follow quarantine rules and what makes it more tolerable. Yesterday, Cochrane published a rapid review on how quarantine affects the spread of COVID-19 (coronavirus).
What is quarantine?
All over the world, public health measures are in place with the aim of reducing the spread of COVID-19, a new virus that spreads quickly and for which there is not yet an effective Something done with the aim of improving health or relieving suffering. For example, medicines, surgery, psychological and physical therapies, diet and exercise changes. or vaccine. These measures include physical distancing (also called social distancing), isolation and quarantine. Quarantine is the separation and restriction of movement of people who have potentially been exposed to a contagious disease, in order to limit its spread. It can be applied to individuals or whole communities. It can be voluntary or enforced.
What did the researchers want to find out?
They wanted to know how well quarantine works in limiting the spread of COVID-19 and if it reduces the number of deaths from the disease. They also wanted to know if quarantine is more effective if it is done along with other things such as closing schools, social distancing and travel restrictions.
What sort of evidence is this?
A Cochrane Rapid Review
Like all Cochrane Reviews, this Cochrane Rapid Review is a systematic review that brings together the best available evidence from research studies relevant to the review’s question(s). However, it follows a shorter process than usual in the interests of providing evidence quickly. It was commissioned by the World Health Organization and has been done as part of Cochrane’s organizational effort to meet the need for up-to-date summaries of evidence to support decision-making in combating the effects and impact of COVID-19.
Based on mathematical modelling studies
It is important to note that the evidence in this review comes from modelling studies that show how quarantine affects the spread of COVID-19. They make assumptions about the viruses and their accuracy won’t be fully known until later. Neil Ferguson, a mathematical epidemiologist at Imperial College London, and lead author of one of the COVD-19 studies included in the review, has reflected on limitations of modelling studies here. He pointed out that “We’re building simplified representations of reality. Models are not crystal balls.”
The models in the studies in the Cochrane Rapid Review are based on assumptions about the true The proportion of a population who have a particular condition or characteristic. For example, the percentage of people in a city with a particular disease, or who smoke. of infection – that’s the percentage of people in a The group of people being studied. Populations may be defined by any characteristics e.g. where they live, age group, certain diseases. who are infected. When we have more information about this, from the COVID-19 pandemic, these may look different. So the Cochrane authors The speed or frequency of occurrence of an event, usually expressed with respect to time. For instance, a mortality rate might be the number of deaths per year, per 100,000 people. their confidence in the results to be low or very low.
The review includes 29 studies, of which ten focused on COVID-19. Nineteen other studies looked at SARS (severe A health condition (or episodes of a health condition) that comes on quickly and is short-lived. respiratory syndrome), alone or with other viruses, and MERS (Middle East respiratory syndrome), so these provide only indirect evidence for our current situation with COVID-19. The ten COVID-19 studies were all modelling studies simulating outbreaks on a cruise ship and in China, the UK, and South Korea.
What’s the bottom line?
The COVID-19 modelling studies in the review consistently report a benefit of quarantine in reducing the number of people who get infected and who die from COVID-19. The studies on SARS and MERS have similar results.
What else does the evidence suggest?
The Cochrane authors also found that putting quarantine in place early and combining it with other public health measures (such as social distancing) seem to be important if it is to be effective in controlling the spread of disease. Early quarantine measures may also mean greater cost-savings are made. The effect of quarantining of travellers from a country with a declared outbreak to reduce disease transmission and deaths was small.
In a press release, lead author Barbara Nußbaumer-Streit talked about the importance of monitoring and reviewing the situation in different localities, saying “This Cochrane Reviews are systematic reviews. In systematic reviews we search for and summarize studies that answer a specific research question (e.g. is paracetamol effective and safe for treating back pain?). The studies are identified, assessed, and summarized by using a systematic and predefined approach. They inform recommendations for healthcare and research. shows that while quarantine may help in containing the COVID-19 outbreak, decision-makers will need to constantly monitor the outbreak situation locally in order to maintain the best possible balance of measures in place, and that there is an acceptable trade-off between benefits and harms.”
On this page, which is constantly updated, you can stay informed about Cochrane content relating to the coronavirus (COVID-19) pandemic and the various related activities that Cochrane is undertaking in response.
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References may be found here.
Sarah Chapman has nothing to disclose.