1)  Exploring novel blood plasma therapy for COVID-19

Context: As part of an innovative step towards treatment of COVID-19 patients, Sree Chitra Tirunal Institute for Medical Sciences and Technology (SCTIMST) has came up with “convalescent-plasma therapy”.
What is convalescent-plasma therapy?

• When a pathogen like novel coronavirus infects, our immune systems produce antibodies. Like the police dogs, the antibodies span out to identify and mark the invading virus. White blood cells attach the identified intruders, and the body gets rid of the infection.
• The therapy, like blood transfusion, harvests the antibody from a recovered patient and ingest into a sick person. Helped by the antibody, the immune system mounts robust combat on the virus.

What are antibodies?

• Antibodies are one of the front-line immune response to an infection by a microbe.
• They are a particular type of proteins secreted by immune cells called B lymphocytes when they encounter an invader, such as a novel coronavirus. 
• The immune system designs antibodies that are highly specific to each invading pathogen. A particular antibody and its partner virus are made for each other.

How the treatment is given?

• Blood is drawn from a person who has recovered from COVID-19 sickness.
• The serum is separated and screened for virus-neutralizing antibodies.
• Convalescent serum, that is the blood serum obtained from one who has recovered from an infectious disease and especially rich in antibodies for that pathogen, is then administered to a COVID-19 patient.
• The sick acquires passive immunisation.

Who will be receiving the treatment?

• At present it is permitted as an experimental therapy for restricted use for severely affected patients only.

How is it different from vaccination?

• This therapy is akin to passive immunization.
• When a vaccine is administrated, the immune system produces the antibodies.
• Thus, in a later date, when the vaccinated person is infected by that pathogen, the immune system releases the antibodies and neutralise the infection. Vaccination provides lifelong immunity.
• In the case of passive antibody therapy, the effect lasts only up to the time the antibodies injected remain the bloodstream.
• The protection given is temporary.
• The mother transfers antibodies through breast milk to an infant before the child could build her own immunity.

What are the Challenges associated with this Therapy?

• This therapy is not simple to harness, primarily due to the difficulty of obtaining significant amounts of plasma from survivors.
• In diseases like COVID-19, where most of the victims are aged, suffering from other medical conditions such as hypertension, diabetes, and so on, not all recovered patients can volunteer to donate blood.

Is it effective?

• Whenever a new viral outbreak takes places, there are no drugs to treat it. Hence, the convalescent serum has been used during past viral epidemics.
• During the outbreak of 2009–2010 H1N1 influenza virus pandemic, patients with an infection requiring intensive care were used.
• After the passive antibody treatment, the serum-treated individuals showed clinical improvement. The viral burden reduced, and the death rate could be lowered.
• The procedure was also useful during the Ebola outbreak in 2018.

Is it safe?

• With modern blood banking techniques that screen for blood-borne pathogens is robust. It is not difficult to match the blood type of donors and recipients.
• Therefore the risks of inadvertently transferring known infectious agents or triggering transfusion reactions are low.

How long the antibodies will remain in the recipient?

• After the antibody serum is given, it will stay on the recipient for at least three to four days. During this period, the sick person will recover.
• Research reports from the USA and China indicate that the beneficial effect of transfusion plasma is obtained in the first three to four days and not later.

2) Clinical protocol exploring the feasibility of convalescent plasma transfusion

Context: Recently, Kerala has got the Indian Council of Medical Research (ICMR) approval for the clinical protocol exploring the feasibility of convalescent plasma transfusion which may be administered to severe Covid-19 patients.
Key Findings

• Kerala has gone a step ahead and won the Indian Council of Medical Research’s approval to explore the feasibility of administering convalescent plasma transfusion on critically ill patients. 
• The move was taken as a precautionary step to be prepared for the more severe second and third waves of the novel coronavirus pandemic.
• Kerala had also sought ICMR’s early clearance for using HIV antivirals (lopinavir/ritonavir) for treating Covid-19 after reports on their potential use surfaced.
• Kerala might need to submit an expanded access protocol to ICMR and Drugs Controller General’s approval and Institutional Ethics Committee approval would be necessary before the administration of the treatment.
• One major challenge is the non-availability of the kit for checking the antibody level in the plasma of a recovered person.
• It is not available in India and has to be brought from Germany.
• The cancellation of international flights would lead to delay in importing the desired number of kits.

About convalescent plasma therapy

• Convalescent plasma therapy involves transfusing certain components from the blood of people who have had the COVID-19 virus and recovered into people who are very sick with the virus or people who are at high risk of getting the virus.

Its working

• As people fight the COVID-19 virus, they produce antibodies that attack the virus. Those antibodies, proteins that are secreted by immune cells known as B lymphocytes, are found in plasma (liquid part of blood that helps the blood to clot when needed and supports immunity).
• Once a person has had the virus and recovered, that person has developed antibodies that will stay in their blood waiting to fight the same virus should it return. Those antibodies, when injected into another person with the disease, recognize the virus as something to attack.
• In the case of the coronavirus, antibodies attack the spikes on the outside of the virus, blocking the virus from penetrating human cells.