Health And Family

Convalescent plasma: What you need to know

Issam Ahmed - Agence France-Presse
Convalescent plasma: What you need to know
Laymis Alvarez (R) takes blood samples from Heather Lieberman, 28, as she participates in a COVID-19 vaccine study at the Research Centers of America (RCA) in Hollywood, Florida, on August 13, 2020. So-called phase three vaccine clinical trials, in which thousands of people take part in the final stages, are gaining traction in Florida. With more than half a million cases and over 9,000 deaths, Florida ranks second in the US in total cases behind California, making it an ideal place to carry out the trials. That has led to a flurry of activity at the RCA, a private center carrying out clinical trials in Hollywood, 25 miles (40kms) north of Miami.

WASHINGTON, United States — The United States has issued an emergency authorization to use blood plasma from recovered COVID-19 patients as a treatment against the disease.

Is it safe and effective? Has President Donald Trump's administration put political considerations ahead of the science? Here's what you need to know.

What is convalescent plasma?

When a person has COVID-19, their body produces antibodies that fight the coronavirus. These proteins float in plasma, the liquid component of blood.

The antibodies can be harvested from patients who have recovered and injected into the blood of others to help them fight the same infection. 

The idea isn't new -- so-called "passive immunization" -- was first tried out against diphtheria in 1892 and later against the 1918 flu pandemic.

Is it safe and effective?

The research into these questions is ongoing, but some early signs have been encouraging.

In June, the Mayo Clinic analyzed the safety of plasma following transfusion in a group of 20,000 COVID-19 patients, finding extremely low rates of side-effects such as heart failure, lung injury, allergic reaction and death.

"We concluded that the use of convalescent plasma was safe," Dr Scott Wright, who led the study that was published in Mayo Clinic Proceedings, told AFP.

Importantly, there was no sign of an effect called "antibody-dependent enhancement," when antibodies that aren't well suited to stopping a virus actually lead to more cells becoming infected.

On the question of how well it works, all experts agree on the need for more clinical trials to compare plasma against standard care.

Dr Soumya Swaminathan, chief scientist of the World Health Organization, said a few smaller trials have reported their findings but "the results, in some cases, point to some benefit, but have not been conclusive."

Another study by Mayo Clinic -- which was not a clinical trial and hasn't yet been peer-reviewed -- suggested plasma helped reduce death rates among hospitalized patients when given early and when the antibody levels were high. 

But there was no placebo, making it hard to read too much into the findings.

It enrolled 35,000 patients and showed that those who received transfusions within three days of their COVID-19 diagnosis had an 8.7 percent death rate in the next week. 

Those who received plasma after four or more days had an 11.9 percent death rate.

Researchers at Johns Hopkins University are meanwhile running a trial in which they are using plasma to immunize patients before they have a chance to get sick. 

Dr David Sullivan, who is leading this trial, compared it to an "immediate vaccine."

If it works, "we can tell people that if you're high risk... you can get this early, and you don't have to worry about going to the hospital," he told AFP.

Some scientists believe that while plasma might be useful right now, in the long-run it might be more advantageous to identify the best antibodies to COVID-19 then synthesize them in labs.

These are known as "monoclonal antibodies" and they are being developed by biotech firms including Regeneron and Lilly.

The advantages are that doctors know precisely what they are getting and can dose accordingly, and the drugs can be mass-produced.

On the other hand, since the virus is continually mutating, antibodies that were produced in a lab to fight an older version might not be as effective as recently-harvested plasma.

Was the authorization politicized?

The Food and Drug Administration (FDA) has previously issued emergency authorizations for antiviral remdesivir, after it was shown to have moderate efficacy against the coronavirus, and for the antimalarial drug hydroxychloroquine, which was subsequently reversed following safety concerns.

Political commentators have questioned the timing of the FDA's latest move as Trump lags in polls before the November election.

Indeed, in making the announcement, both Trump and FDA Commissioner Stephen Hahn misrepresented a key statistic when they said that plasma reduced mortality rates by 35 percent.

FDA spokeswoman Emily Miller later clarified on Twitter that the figure referred to the relative reduction in mortality risk for people who received high-levels of antibodies in the Mayo Clinic study compared to those who received low-levels.

"It does undermine the credibility of the entire United States government and the administration but specifically these institutions," said Dr Matthew Heinz, a physician in Arizona who served in former president Barack Obama's health department.

But Dr Daniel Hanley, who directs Johns Hopkins' multisite clinical trials, said that early results had met the threshold for emergency approval. 

"One thing to emphasize is this information is coming in faster than it has in any other pandemic," he told AFP.

As It Happens
LATEST UPDATE: September 24, 2021 - 4:58pm

Follow this page for updates on a mysterious pneumonia outbreak that has struck dozens of people in China.

September 24, 2021 - 4:58pm

Russia records its highest daily coronavirus death toll with 828 fatalities reported over the past 24 hours. 

The new figures bring Russia's total deaths from COVID-19 to 202,273 -- the highest toll in Europe. — AFP

September 22, 2021 - 1:59pm

Brazil's Health Minister Marcelo Queiroga tested positive for Covid-19 Tuesday after attending the UN General Assembly in New York that was inaugurated by his president, Jair Bolsonaro, according to an official statement.

"The other members of the delegation have been tested and are negative," said the official Brazilian government press release.

Queiroga, who had received a Covid-19 vaccine, was the second member of Bolsonaro's entourage to test positive for the virus since arriving in New York for the UN gathering. — AFP

September 21, 2021 - 6:52pm

The novel coronavirus has killed at least 4,696,559 people since the outbreak emerged in China in December 2019, according to a tally from official sources compiled by AFP.

At least 229,008,620 cases of coronavirus have been registered.

The vast majority have recovered, though some have continued to experience symptoms weeks or even months later.

September 20, 2021 - 8:29pm

The COVID-19 pandemic sped up the shift of innovation from Europe and North America towards Asia, UN world rankings showed Monday.

The Global Innovation Index 2021, from the United Nations' World Intellectual Property Organization, showed surging performances by South Korea and China.

"The pandemic has accelerated the long-term geographical shift of innovation activities toward Asia, even if Northern America and Europe continue to host some of the world's leading innovators," said WIPO.

While the top four in the global rankings remained the same as last year — with Switzerland leading for the 11th year running followed by Sweden, the United States and Britain — South Korea leapt five places to fifth.

The index found "substantial increases in brand values in Korea, in trademarks being filed, but also in cultural and creative services exports," index co-editor Sacha Wunsch-Vincent told reporters, citing the K-Pop phenomenon. — AFP

September 19, 2021 - 4:17pm

Australia's second-largest city will exit its coronavirus lockdown in late October if vaccine targets are met under an official roadmap released Sunday.

About five million people in Melbourne have been under stay-at-home orders since August 5, the sixth lockdown they have endured so far during the COVID-19 pandemic.

Officials in Victoria state, which includes Melbourne, announced those orders would be lifted when 70 percent of over-16s are fully vaccinated. They projected that target would be reached around October 26.

"Lockdown will end. The (limited) reasons to leave your home and the curfew will no longer be in place," Victoria premier Dan Andrews said, adding that a raft of restrictions would still be enforced.

Restaurants and pubs will be allowed to reopen but only with a maximum of 50 fully vaccinated people seated outdoors, while a ban on visitors to homes will remain in place. — AFP

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