(QCOSTARICA) In a phrase, convalescent plasma therapy is about removing plasma from patients who have already recovered from SARS-CoV-2, the covid-19-transmitting coronavirus, and administering it to critically ill patients fighting the disease.
The therapy is an experimental treatment. It is not a new treatment, but it is not that common either, because it is not easy to achieve.
People who’ve recovered from COVID-19 have antibodies — proteins the body uses to fight off infections — to the disease in their blood. The blood from people who’ve recovered is called convalescent plasma. Plasma is the liquid portion of the blood.
Researchers hope that convalescent plasma can be given to people with severe COVID-19 to boost their ability to fight the virus. It also might help keep people who are moderately ill from becoming more ill and experiencing COVID-19 complications.
In Costa Rica, the Caja Costarricense de Seguro Social (CCSS) is already implementing it.
La Nacion, in its explainer report, used the knowledge and help of Dr. Olga Arguedas, immunologist and director of the National Children’s Hospital.
What is plasma?
Plasma is the liquid part of blood. 55% of our blood is made up of plasma. Once removed, the plasma has a translucent yellowish color.
Blood contains cells such as red blood cells, white blood cells, platelets, etc., and it also contains a liquid fraction: plasma.
The latter is basically made up of water, salt, and proteins that include immunoglobulins, which are liquid defenses (the predominant antibody in the blood).
Plasma also has clotting factors and it also has another very important protein called albumin. It is responsible for keeping fluids in place within the body without seeping into other tissues, and it also handles the transport of many medications.
In short, plasma is the liquid fraction of blood that is particular interest right now is to overcome covid-19, treating the sickest with its immunoglobulins, which are specific defenses against infectious agents to which a person has been exposed.
The results are modest, says Arguedas, but there are patients that it has helped them. This procedure has been useful in Chile, the United Kingdom and Austria. Especially in serious patients.
“In this complex scenario for a life-threatening disease, without evidence-based treatment, plasma is one more alternative to consider,” explains Arguedas. “The most important effects have been seen in achieving improvement in pneumonia so severe that covid-19 produces. The critical patient is the patient for whom this therapy is best indicated. It is not in other patients because it is a delicate form of therapy, which requires very strict medical control, and for which there are also some undesirable effects.”
During the press conference on Monday, May 25, Dr. Román Macaya, President of the CCSS, confirmed that the convalescent plasma is being currently applied to a 37-year-old patient at the Specialized Covid-19 Patient Care Center (CEACO ).
According to Macaya, Costa Rica has collected 61 bags of convalescent plasma from 25 donors.
The fact that this plasma is not used in all active patients does not have as much to do with availability. Although there is little availability because in Costa Rica there are still not too few recovered patients, this treatment is not indicated in patients who are not in critical condition, emphasizes the immunologist Olga Arguedas.
“Because the risk-benefit balance in patients who are not in critical condition is not adequate,” she says.
In the United States, the National Institutes of Health (NIH) calls for recovered patients to donate their plasma for the same treatment. As of May 5, 2020, the NIH had the following to say about the results of the convalescent plasma application:
“Although the results are promising, convalescent plasma has not been shown to help every time in the treatment of covid-19. This procedure has been applied to a small number of people in preliminary studies, and some of them have been improved”.
How difficult is it to extract plasma and apply it to sick patients?
“Not all countries can give convalescent plasma therapy because this requires very sophisticated laboratory equipment, apheresis machines, a series of biosafety standards that must be met with convalescent plasma,” explains Dr. Arguedas.
Costa Rica has an advantage, the Clodomiro Picado Institute of the University of Costa Rica and working with the CCSS Blood Bank have managed to perform plasmapheresis to attend to the covid-19 emergency.
“It is a great achievement, and indeed it is one of the few countries that achieves this for this pandemic,” says pediatric infectologist María Luisa Ávila, and former Minister of Health of Costa Rica (2006 and 2011).
“However, it is a process that is known for a long time and has been used for other infectious diseases, but now with better technology. It is a clear example that Costa Rica has the capacity to do great things,” added Avila.
UCR Tropical Diseases Research Center (CIET) microbiologist, Eugenia Corrales-Aguilar, a doctor of Virology and university professor, says that when making any blood transfusion or, in this case, plasma, one must be very careful regarding the risk biological that implies.
“The product must be very well controlled. Because it could cause an infection in the person who will receive the blood product. You have to sift very well. You have to detect the genetic information of the liquid beforehand”.
According to Corrales-Aguilar, five factors mean that not all countries can apply convalescent plasma to covid-19 patients:
- A very robust blood bank is required.
- Very robust biological control is required.
- Recovered patients who donate their plasma need to be patients with clean blood (not having any other transmissible microorganism).
- You need to have an established capacity to measure the immune response to covid-19.
And you need to be highly prepared: “You can always cause an adverse reaction. People receiving these antibodies must be monitored to check that they are not having a reaction against that plasma. You have to have a very robust health system and ‘spark’ to measure those signs of whether the person is reacting badly, and try to manage it. The final objective is to try to collaborate with the improvement of the patient and not worsen his situation. This is what should be put on a scale, and many countries do not have the knowledge to do it,” Corrales-Aguilar.