New Delhi, Even as a group of scientists are racing against time to develop a vaccine against COVID-19 so that new infections can be prevented, experts are now pinning a lot of hope on effectiveness of blood-related therapies being investigated in some countries.At the centre of these blood-related therapies are the people who have recovered from the dreaded disease.

Worldwide, nearly 250,000 people have recovered from COVID-19, while about 65,000 of about 12 lakh infected people have succumbed to the disease.

The US is investigating the effectiveness of two blood related therapies called convalescent plasma and hyperimmune globulin.

These are antibody-rich blood products made from blood donated by people who have recovered from the infection caused by the virus.

Convalescent plasma is the liquid part of blood that is collected from patients who have recovered from an infection. Antibodies present in it are proteins that might help fight the infection.

Hyperimmune globulin is a biological product manufactured from convalescent plasma.

The US started these investigations after positive results emerged from China.

"Based on prior experience with respiratory viruses and on data that have emerged from China, these products have the potential to lessen the severity or shorten the length of illness caused by COVID-19," the US Food and Drug Administration (FDA) said in a statement on April 3.

According to Neha Gupta, Infectious Diseases Consultant at Fortis Memorial Research Institute in Gurugram, based on the type of severity of COVID 19 infection, immunity develops.
Immunity develops early in asymptomatic or persons with mild symptoms, while it develops later in severe and critically-ill COVID 19 patients, she explained.

"Antibodies from the convalescent serum (of patients who have recovered from COVID 19) may offer an option for prevention and treatment of COVID-19 disease," she told IANS, adding that some recent experiments showed lower mortality rate for plasma-treated patients compared to control patients.

But much still remains to be known about the effectiveness of these therapies.

"Humans make antibodies when they are infected with a virus and it generally provides immunity to reinfection. But SARS-CoV-2 (the virus that causes COVID-19) is a new virus and we don't know that there is going to be immunity for few months or long term," Navin Kumar, Head of Clinical Virology & Infection Prevention, Manipal Hospitals, New Delhi, told IANS.

"The plasma from recovered patients (convalescent plasma) have been used for treating many viral infections but not much is known about how effective it is for treating COVID-19.

"There are few reports of successful treatment from other countries but no good research studies are there to support its routine use and what is the best time to use during the illness. At this moment it is considered as an experimental treatment," Kumar said.

Japan-headquartered global bio-pharmaceutical company Takeda has already initiated development of a plasma-derived therapy to treat high-risk individuals with COVID-19.

"As a leader in plasma-derived therapies with more than 75 years of experience in the development of plasma-derived products, Takeda has the expertise to research, develop, and manufacture a potential anti-SARS-CoV-2 polyclonal H-IG (hyperimmune globulin), which Takeda is referring to as TAK-888," the company said last month.

Takeda said it is currently in discussions with multiple national health and regulatory agencies and health care partners in the US, Asia, and Europe to expeditiously move the research into TAK-888 forward.

It goes without saying that without a vaccine at their disposal, the world is waiting with bated breath for the success of any therapy to effectively beat the virus behind the pandemic.