Cochrane evidence on COVID-19: a round-up

Sarah Chapman highlights Cochrane evidence on COVID-19 and other health effects of the pandemic, with links to reviews, blogs and other Cochrane resources. 

While we’ve all been adapting to huge and sudden changes in our lives and healthcare workers have been meeting unprecedented challenges, scientists have scrambled to produce research evidence relevant to the pandemic. Cochrane is responding by producing rapid reviews of this new evidence on priority topics, and these are updated as new evidence emerges. They show that much of the research that has been done so far leaves us with more unanswered questions than answers, but we must hope that this changes as new studies are available to add to the reviews.

Here’s a round-up of some of the Cochrane evidence so far.

Detecting COVID-19

Measures to control the spread of COVID-19

Treating people with COVID-19

The impact of the pandemic on other areas of health and wellbeing

Coronavirus (COVID-19): Special Collections

Coming up…

Have your say about what type of COVID-19 evidence is most useful to you

Signs and symptoms of COVID-19

We’re hearing a lot about temperature checks, which in many places are being used determine whether someone may enter a care home, hairdressers or other building. But what’s the evidence? We’ve blogged about a Cochrane Review, published in July 2020, on the accuracy of any signs and symptoms, either alone or in combination, for diagnosing COVID‐19.

A Cochrane Review has looked at the available evidence on the accuracy of clinical signs and symptoms for diagnosing COVID-19. Based on the currently available evidence, neither absence nor presence of signs or symptoms are accurate enough to rule in or rule out disease. There is a need for evidence on combinations of signs and symptoms and in different settings (particularly GP practices) and age groups (children, older adults). This living systematic review will be updated as often as is feasible to take account of new evidence as it emerges. 

You can read the blog: “Signs and symptoms of COVID-19: new Cochrane evidence“. There is also a podcast and a Cochrane Clinical Answer.

Antibody tests for COVID-19

Antibody tests have the potential to identify people who have had COVID-19. A Cochrane Review ‘Antibody tests for identification of current and past infection with SARS-CoV-2′ was published in June 2020 and we have blogged about it: “Antibody tests for COVID-19: new evidence on test accuracy and some considerations“.

Take-home pointsAntibody tests have the potential to identify people who have had COVID-19.A Cochrane Rapid Review shows that antibody tests could have a useful role in detecting if someone has had COVID-19. As with any diagnostic test, there will be a number of people falsely diagnosed as having COVID-19, and a number of people who do have the disease will be missed; timing makes a big difference to the accuracy of the test.Test accuracy is only one consideration in decisions about the purposes and implications of widespread testing for COVID-19 antibodies.

Rapid tests for COVID-19, done during a health care visit

Tests to detect COVID-19 that can give a result ‘while you wait’ (within a couple of hours) could be really useful, helping people isolate quickly to reduce the spread of infection.  A Cochrane Review on Rapid, point‐of‐care antigen and molecular‐based tests for diagnosis of SARS‐CoV‐2 infection was published in August 2020. The review authors anticipate that they will have an update of the review this autumn and lead author Jacqueline Dinnes is going to blog about the updated review here.

Quarantine for controlling COVID-19

A Cochrane rapid review on quarantine alone or in combination with other public health measures to control COVID-19 was published in April 2020 and updated in September 2020. It is the focus of this blog: “Quarantine for controlling COVID-19 (coronavirus). New Cochrane evidence.”

A Cochrane Rapid Review, updated in September 2020, has found that COVID-19 mathematical modelling studies consistently report a benefit of quarantine in reducing the number of people who get infected with COVID-19 and who die from it. The number of studies has increased significantly in a short space of time since this review was first published in April 2020, but the evidence base is still limited. This is because most studies on COVID-19 are mathematical modelling studies that make different, important assumptions (for example, about how quickly the virus would spread). This Rapid Review was done in a short space of time 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. More Rapid Reviews, answering other important questions about COVID-19, are underway.

You might also be interested in this blog ““Stay at home” rules: what makes people more likely to stick to quarantine?“, which looks at two non-Cochrane rapid reviews from researchers at King’s College London.

Contact tracing

Contact tracing aims to reduce transmission of infection by identifying people who have been in contact with someone who has it, so that they can isolate. A Cochrane rapid review published in August 2020 looked at evidence on digital contact tracing technologies in epidemics.

The review highlights an evidence gap, the authors concluding that “the effectiveness of digital solutions is largely unproven as there are very few published data in real‐world outbreak settings.”

Personal Protective Equipment (PPE) for healthcare workers

Two Cochrane reviews contribute to the evidence base on PPE for healthcare workers and we have a blog about these: “Personal protective equipment (PPE) for healthcare workers: new Cochrane evidence“. They look at Personal protective equipment for preventing highly infectious diseases due to exposure to contaminated body fluids in healthcare staff (May 2020) and Barriers and facilitators to healthcare workers’ adherence with infection prevention and control (IPC) guidelines for respiratory infectious diseases: a rapid qualitative evidence synthesis (April 2020).

Take-home points • An updated review and a new rapid review on PPE have been produced 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. • These reviews contribute to the evidence base about a range of considerations in PPE use, including barriers and facilitators to healthcare workers adherence to infection prevention and control guidelines. There are some new, creative solutions being developed to address some of the issues associated with wearing PPE.

For the review on PPE there is a Cochrane Clinical Answer. For the review on barriers and facilitators there is podcast and a Cochrane Clinical Answer. Evidence Synthesis Ireland and Cochrane Ireland have also created an infographic summarising key messages.

Convalescent plasma – a possible treatment for COVID-19?

Many clinical trials are being done to investigate the potential benefits or harms of using plasma from people who have recovered from COVID-19 to treat people who are currently ill with it. This blog: “Convalescent plasma to treat people with COVID-19: the evidence so far” looks at a Cochrane rapid review on convalescent plasma to treat people with COVID-19, updated in July 2020.

A Cochrane rapid review with 20 studies, including one small randomized controlled trial, shows that the effectiveness and safety of convalescent plasma for people with COVID-19 are uncertain. The review authors identified 98 ongoing studies, including 50 randomized trials. This review is being regularly updated as a ‘living systematic review’, based on monthly searches for new evidence, and the results are likely to change.  

Oxygen therapy for adults in intensive care with acute respiratory distress syndrome

A Cochrane rapid review on oxygen targets in the intensive care unit during mechanical ventilation for acute respiratory distress syndrome has brought together evidence on this topic. The review authors explain the context:

Acute respiratory distress syndrome (ARDS) is a very severe breathing problem with a high mortality rate (chance of dying). It has many potential causes, including viral infections such as COVID‐19, and there are no specific treatments for it except for giving patients oxygen via a ventilator (artificial breathing machine) on an intensive care unit, often for long periods of time. However, large amounts of oxygen (either a high concentration of oxygen or oxygen administered for a long period of time) are associated with increased harm due to other illnesses (e.g. heart attack or stroke).”

Here’s what they found:

Patients with acute respiratory distress syndrome (ARDS) and receiving oxygen through a breathing tube in intensive care may be more likely to survive beyond 90 days if they receive higher volumes of oxygen, compared with lower volumes. Whether patients receive a higher or lower volume of oxygen may make little or no difference to the number of days ventilated; the need for inotropic support (to stabilise circulation and optimise oxygen supply); or the likelihood of needing renal replacement therapy. However the evidence is very uncertain (all very low-certainty evidence). Effects on quality of life were not reported.The evidence is very uncertain about the potential harms of higher versus lower oxygen targets (very low-certainty evidence). Cochrane Review (published September 2020); one study with 205 mechanically ventilated patients in an intensive care setting, comparing conservative oxygen therapy with liberal oxygen therapy for seven days.

Interventions for heavy menstrual bleeding

Pandemics disrupt healthcare provision. With this in mind, a Cochrane overview of reviews (July 2020) has been done on interventions commonly available during pandemics for heavy menstrual bleeding. You can see summaries of the review here, including an infographic to help women make choices about treatment. There is also a podcast about this review and two Cochrane Clinical Answers. 

Routine vaccinations during the pandemic

The World Health Organization (WHO) has emphasized the importance of keeping up with routine vaccinations during the pandemic, advice endorsed by Public Health England. A Cochrane Review on vaccines for measles, mumps, rubella and varicella  in children (published April 2020) was discussed in this blog: “MMR vaccines: do they work and are they safe?“.

Take home points A Cochrane Review has shown that MMR vaccines are effective at preventing measles, mumps, rubella in children.The review found no evidence of an increased risk of autism from MMR vaccination.World Health Organization guidance, supported by Public Health England, advises having routine vaccinations during the COVID 19 pandemic.It is never too late to catch-up on MMR vaccination.

There are two Cochrane Clinical Answers related to this review.

Social isolation and loneliness in older people

With restrictions imposed during the pandemic increasing isolation for many, a Cochrane rapid review (May 2020) looked for evidence on video calls for reducing social isolation and loneliness in older people. We discuss the review in this blog: “Loneliness in older people: could video calls help?

Video calls have the potential to help older people stay connected with others and to reduce loneliness and social isolation. A Cochrane rapid review has highlighted that the evidence on the effects of video calls on loneliness, depression, quality of life and social isolation are very uncertain. It is important to consider an older person’s circumstances as well as their personal preferences for technology such as video calls.

There is also a podcast and a Cochrane Clinical Answer.

Quitting smoking to improve respiratory health

Given the current threat from COVID-19, an acute respiratory infection, there has never been a better time to stop smoking, and the World Health Organization is urging people to do so. We have looked at evidence from a new Cochrane Special Collection, COVID-19: Effective options for quitting smoking during the pandemic, in this blog: “Smoking and coronavirus (COVID-19): time to quit.”

Smoking increases the risk of getting acute respiratory infections and of being more severely affected, as does exposure to second-hand smoke. The Cochrane Special Collection, COVID-19: Effective options for quitting smoking during the pandemic, pulls together evidence including Cochrane Reviews on nicotine replacement, behavioural support such as telephone, internet and text messaging programmes, and gradual quitting. The Cochrane Reviews in the Special Collection focus on interventions that are feasible under public health measures that restrict face to face contact with health practitioners.

The Special Collection on quitting smoking during the pandemic is one of seven Cochrane Special Collections on COVID-19. Developed with experts from our global Cochrane network, they are based on World Health Organization interim guidance, and continuously updated.

Like the reviews themselves, we update our blogs to reflect the latest evidence. There are new reviews coming up, as well as updates of existing reviews, so check back for additions to this blog. Among others, we are anticipating a suite of three reviews on mouthwashes/nasal sprays to protect healthcare workers and patients from COVID-19 infection and a review on travel restrictions.

Keeping up to date

As well as coming back to this blog, you can find Cochrane resources and news on COVID-19 here and this will also be continually updated.

What COVID-19 evidence have you found useful and what would you like to see in the future? Please complete this Cochrane survey to let us know. Thank you.

References (pdf).

Join in the conversation on Twitter with @CochraneUK @SarahChapman30 or leave a comment on the blog. Please note, we will not publish comments that link to commercial sites or appear to endorse commercial products.

Sarah Chapman has nothing to disclose.

Editor’s note: This blog was last updated on the 14th September 2020.



Cochrane evidence on COVID-19: a round-up by Sarah Chapman

is licensed under a Creative Commons Attribution-NoDerivatives 4.0 International

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