by NUR HANANI AZMAN/ pic by TMR FILE
DOCTORS harvesting antibody-rich plasma from a convalescent patient and administer it immediately in another infected patient to prevent or treat infections is called passive immunity.
However, the antibody proteins will only last from a few weeks to a few months, said KPJ Damansara Specialist Hospital paediatric consultant Datuk Dr Musa Mohd Nordin.
He said this has already been used to treat measles and varicella (chicken-pox) patients with measles immunoglobulin and varicella-zoster immunoglobulin.
“Eleven critically ill Covid-19 patients in New York and Houston had been treated with Coronavirus Immunoglobulin (CIG) since March 28.
“The US Food and Drug Administration authorised its emergency use, utilising plasma from other patients who have recovered from the coronavirus infection,” he told The Malaysian Reserve yesterday.
This is part of the National Covid-19 Convalescent Plasma Project where it will study whether the convalescent plasma can prevent infection in people exposed to Covid-19 against a placebo, he explained.
A second trial will study whether plasma can prevent moderate Covid-19 infections from becoming severe and requiring intensive care, while a third study will see whether the therapy helps the most critically ill patients.
Convalescent plasma was used in the 2003 SARS-CoV1 and 2013 MERS-CoV outbreaks. They showed benefit but was not controlled with a placebo arm.
Musa said the body’s immune system makes antibodies in response to an attack by bacteria and viruses. It might take between 10 and 14 days for the body to produce IgM and IgG antibodies against the SARS2 coronavirus.
“This is called active immunity and can last many years.
“For antibodies against viruses like measles, mumps, rubella and chicken-pox, it can last a lifetime,” he said.
Vaccines, through the administration of weakened viruses, dead bacteria or toxoid ramps up antibody production and also induces active immunity.
Musa said in Shenzhen, China, five patients were successfully treated with CIG. Three have been discharged and two are in stable condition.
However, they were also given antiviral medications, therefore it is unclear which therapy, if any, was the critical success factor.
“The Spike Protein (SP) on the coronavirus pierces and invades the human cells, taking over the cell processes to make many copies of itself.
“The thinking is that the antibody sticks itself to the virus and destroys it, thus preventing the SP from binding to the human cell, preventing its entry, and blocking infection and cloning itself in the human cells,” he added.
On the other hand, as the plasma treatment for Covid-19, where the liquid component in the blood taken from a survivor, is still at the experimental stage, some experts are saying that more scientific evidence is needed.
A physician and gastroenterologist hepatologist consultant, who did not want to be identified, said each person is different and one case does not represent the others.
“We need to get the right information from an infectious disease specialist and update from the Health Ministry,” he added.
Recently, Bernama reported that a recovered Covid-19 patient was chosen as the first plasma donor in the country.
It was reported that his blood plasma was found to be strong, healthy and suitable for facilitating the treatment of critical Covid-19 patients.
The man, who had the opportunity to ask the doctor some questions on plasma treatment, said not everyone is qualified to be a plasma donor.
The person must be free from any chronic illness, not on any long-term medication and completely healthy.
On how he was infected, the 41-year-old said he was infected during the second wave of the outbreak in the country.