Plasma therapy: Some recovered COVID patients have richer antibodies than others, study finds

While there is no single approved treatment method for COVID-19, convalescent plasma therapy (CPT) has fast emerged as a way to treat COVID and speed up recovery. The therapy, which transfuses plasma rich antibodies from a recovered patient onto another positive patient has been touted to cut down mortality rate and aid recovery for patients, especially those who have low immunity.

Even though it's an experimental therapy, there's a lot of research being done on the helpful properties of antibodies. COVID recovered patients are being requested to donate plasma. It's also a procedure which can be done repeatedly with no recorded side-effects.

While there are people who can't donate plasma, a new study has found that recovered COVID patients who have a certain type of symptoms are more eligible for plasma donation. If the study is true, it might offer a lot more insight into the many different ways COVID impacts our immunity.

A joint study done by researchers from USA and Denmark found that out of those who donate plasma, those with more typical COVID symptoms, such as fever, shortness of breath, nausea, pharyngula had a higher level of antibodies (Immunoproteins, IgG levels) than others with less prominent symptoms.

For the study, researchers used a flexible ELISA based detection tool which helped identify SARS-CoV-2 antibodies in 350 mild, moderate, critical and asymptomatic COVID-19 recovered patients. 580 plasma samples from healthy volunteers collected before the pandemic spread were also analyzed for the same.

Different kind of immunoproteins were then sampled against SARS-COV-2 protein to see how helpful they were.

Patients with more symptomatic COVID were found to have more lasting antibodies 40 days post-infection than the ones who had fewer symptoms or were asymptomatic.

A stark difference in IgG levels was observed, amongst those who were critically ill and those who were not. While IgG levels spiked up for those with more typical and severe symptoms, a low level was measured in those suffering from mild symptoms, or those affecting the upper respiratory tract (including loss of smell or taste).

Basis of the study, scientists suggest that tools like these could help ascertain how helpful plasma therapy could be in treating a COVID-positive patient. Currently, no specific sero tests are conducted on patients willing to volunteer for donation. A volunteer just has to be COVID symptom-free for 14 days and should not carry any infection in the blood.

Another recent study which has been published in the journal, 'Viruses' showcased that the antibody titlers, which help in plasma therapy were found to the most helpful in those who suffered from a recent infection. Blood plasma from several recovered patients was cultured to see how effectively they were able to neutralize the virus. It was then seen that the more recent recovery it is, the more effective antibodies are.

If this is true, it might give more clue to the fact that antibodies, do start to wane off and lose their potential after some months, which was published in a study done by King's College, London.

Despite proof which suggests that plasma therapy is a decent cure to hail recovery, some experts believe that there is much evidence to show that plasma therapy could be our best bet of defence.

AIIMS Director, Dr Randeep Guleria, in a statement a month back said that there's still not enough conclusive evidence to prove that plasma therapy could save lives.

“It is just one part of the treatment strategy. It helps improve the person’s own immunity by giving what we call passive immunity because the antibodies in the plasma enter the blood and try to help fight the virus in the afflicted individual. It is not something which will dramatically make a difference.

Interestingly, even though several plasma banks have been set up across cities, plasma therapy is not an approved treatment by the WHO or CDC.

As doctors say, extensive surveys and randomized trials need to be done to consider this a good fit to combat COVID.