22nd Jun 2020

COVID-19 FAQ: how donated blood from recovered patients can help people with severe cases?

22nd Jun 2020

Curated by Endre Szvetnik

‘Convalescent plasma therapy’ (CPT) – using the antibody-containing blood components of recovered COVID-19 patients – could be an effective treatment for people critically sick with the disease.

Blood plasma from recovered patients is administered via IV.

This is according to a recent systemic review, a type of research paper considered as the strongest in evidence-based medicinal studies. CPT treatment uses the blood plasma of former COVID-19 patients, who have developed antibodies that can protect them from future SARS-CoV-2 infection. In the absence of COVID-19 vaccines, convalescent plasma has been given to severely ill people – often on ventilation - to help them recover from the disease. The authors of the systemic study picked 5 papers out of 110 to focus on data of convalescent plasma-treated patients. The 27 persons observed across the five studies received CPT between Day 6 and 50 of developing symptoms or being admitted to hospital. They were also treated with antiviral drugs. The studies found that following CPT, the amount of circulating virus was significantly reduced and the number of antibodies increased in their blood between the first and 30th day of treatment. All patients in the studies have survived and tolerated CPT well, and those on ventilation were removed from it between the first and 35th day after receiving the transfusion.

Has it been tried before and how is it administered? CPT has a long history stretching back to the late 1890s. Convalescent plasma was given to patients and reduced the number of deaths in the 1915-1917 Spanish flu pandemic, during the 2003 SARS pandemic and the 2006-2008 avian flu outbreaks. Recovered COVID-19 patients are encouraged to donate blood so that its plasma can be extracted and given to severely sick COVID-19 patients in hospitals. Patients get a syringe connected to a tube inserted into a vein on their arms and are administered the plasma through a drip-feed. The procedure lasts for 1-2 hours. In some studies, concerns have been raised about the use of convalescent plasma in the treatment of COVID-19. Some adverse effects were observed among patients, such as transfusion-related lung injury or circulatory overload, which was observed in 12% of at-risk patients. Therefore more randomized clinical trials are important to prove the safety and dosage of such treatments. The first such trial was inconclusive because it did not manage to recruit the desired number of people, so more results are needed to clearly define the benefits and use of CPT in caring for COVID-19 patients. The NHS in the UK, the Royal College of Surgeons in Ireland and the Medical University of Bahrain and Australia are currently collecting convalescent plasma and conducting clinical trials that are expected to yield more detailed results.

Here is the current state of science on a Sparrho pinboard. NB: The pinboard contains research papers that have not been peer-reviewed yet, meaning that they have not gone through the standard scientific validation process yet.

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Curated by

Endre Szvetnik

Endre Szvetnik is Senior Editor at Sparrho. Endre works with Sparrho Heroes to curate, translate and disseminate scientific research to the wider public.

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