How plasma therapy works, what India plans
GS Paper III
Topic: Science and Technology
Mains: Convalescent plasma therapy
What’s the News?
To look for therapeutics to fight the novel coronavirus disease (COVID-19), India is all set to try out a therapy that involves attempting to jump-start the immunity of a serious patient by infusing some of the blood plasma of a person who has already recovered from the disease.
- At present there are no specific antiviral agents which have been found to be effective in the treatment of COVID-19.
- Convalescent plasma therapy is not new and has been used by doctors to treat critically ill patients during earlier epidemics too, during H1N1, SARS and Ebola.
- When reports that HIV antivirals (lopinavir/ritonavir) might be potentially useful in treating COVID-19 patients, then too Kerala had sought ICMR’s early clearance for the protocol in January itself.
Coronavirus: Stages of a pandemic
- First stage: In the first stage of a disease cases of an epidemic are imported into a country in which the infection did not originate and it eventually takes the form of a pandemic sweeping the globe.
- Second stage: The second stage is when the virus starts being transmitted locally.
Local transmission means that the source of the infection is from within a particular area and the trajectory the virus has taken from one person to the next is clearly established.
- Third stage: The third stage is that of community transmission which means that the virus is now circulating in the community, and can infect people with no history either of travel to affected areas or of contact with an infected person.
- If and when community transmission happens, there might arise the need for a full lockdown because in that situation it is theoretically possible for every person, regardless of where they are from and who they have been in contact with, to spread the disease.
- Fourth stage: from pandemic to endemic It is when the disease, COVID-19 in this case, becomes endemic in some countries.
Convalescent plasma therapy:
- It involves transfusion of the blood plasma of a recovered patient into another patient.
- Plasma is the matrix on which the blood cells float. It also houses crucial components of immunity known as antibodies.
- Antibodies are the immediate warriors who fight an invading pathogen – an antigen – to defeat it.
- Once that is done, some blood cells function as memory cells so that they can identify and defeat the same enemy if and when it invades again by quickly producing the same antibodies.
- Convalescent plasma therapy banks on the age-old concept of passive immunity when antibodies for some diseases, such as diphtheria, were developed in horses and injected into humans.
- Active immunity is what is achieved by introducing an attenuated pathogen (such as the BCG vaccine) into the body to generate an immune response. The other kind of immunity is passive immunity.
- While the ICMR has cleared the clinical trial protocol, the State might at some point need to submit an expanded access protocol to the council, so that severely ill patients can be administered the treatment on compassionate grounds.
- Drugs Controller General’s approval and institutional ethics committee approval would have to be there before the treatment can be administered.
- The country’s apex medical research organisation, Indian Council of Medical Research (ICMR), is framing a protocol for infusing blood plasma from people who have recovered from COVID-19 into serious patients.
- This will only be done by way of a clinical trial, in patients who are in a severe condition, or on ventilator.
Hydroxychloroquine: The drug everyone is looking at
GS Paper III
Topic: Science and technology
Prelims: Hydroxychloroquine and its uses
What’s the News?
- The government has decided to ease its ban on the export of hydroxychloroquine, a drug that has garnered global interest in the treatment and prevention of COVID-19.
- On Tuesday, US President Donald Trump tweeted about “retaliation” if India did not heed his request for the drug.
- Later, India said it would supply to countries that needed it the most, and to neighbours who were “dependent on India’s capabilities”.
Hydroxychloroquine and its uses:
- It is an antimalarial drug option, considered less toxic than chloroquine, and prescribed in certain cases.
- Doctors also prescribe hydroxychloroquine for patients of rheumatoid arthritis and lupus.
- Hydroxychloroquine had a market size of only around Rs 152.80 crore in the 12 months ended February 2020, according to pharmaceutical market research firm AIOCD Awacs PharmaTrac. However, several countries source the drug from India.
Why has the COVID-19 outbreak spotlighted hydroxychloroquine?
- In a study last month in the International Journal of Antimicrobial Agents (IJAA), French scientists reported: Twenty cases were treated and showed a significant reduction of the viral carriage compared to controls, and much lower average carrying duration than reported of untreated patients in the literature.
- Azithromycin (an antibiotic) added to hydroxychloroquine was significantly more efficient for virus elimination.
- The study was flagged as being too small to draw a definitive conclusion.
- On April 3, the International Society of Antimicrobial Chemotherapy, which owns the IJAA, said the study did “not meet the society’s expected standard, especially relating to the lack of better explanations of the inclusion criteria and the triage of patients to ensure patient safety”.
U.S government reaction:
However, by March 21, Trump had begun to call the drug a “game changer”, and has since been pushing it.
Indian government reaction:
- At the end of last month, the Indian Council of Medical Research (ICMR) issued an advisory recommending the use of hydroxychloroquine in asymptomatic healthcare workers treating COVID-19 patients, and also allowed doctors to prescribe it for household contacts of confirmed COVID-19 patients.
- However, the government has stressed that the drug can only be used in COVID-19 treatment on prescription, and that it should not instill a sense of “false security”.
Effectiveness of the drug:
- Two large trials are under way on the effectiveness of hydroxychloroquine, and even chloroquine, in COVID-19 treatment.
- In the World Health Organization (WHO) solidarity trial, of which India is a part, clinicians worldwide are to follow a common protocol to treat patients with hydroxychloroquine.
- The second is the chloroquine accelerator trial, largely funded by the Wellcome Trust and the Bill and Melinda Gates Foundation.
- The US has been looking to procure the drug for emergency use. On March 21, Ipca told stock exchanges here that the US Food and Drug Administration had “made exception” to its import alert against the company so that it could get stocks.
- India decided to ban exports of the drug on April 4. On Tuesday, the government decided to ease the ban.