Back when former President Donald Trump came down with Covid-19 in October 2020, the world was a lot different than today, when the White House announced President Joe Biden had contracted the illness.

Scientists in Trump’s era were still looking for the best ways to treat the disease, and rates of severe illness and death were much higher. The then-president received the highest standard of care any American could hope to get, but these were the earliest tools at hand. 

They included a then-experimental monoclonal antibody cocktail from Regeneron Pharmaceuticals Inc. At Walter Reed National Military Medical Center, where he was hospitalized for three nights, he also received the steroid dexamethasone and Gilead Sciences Inc.’s infused antiviral remdesivir.

But so far, Biden’s treatment has been a much more straightforward affair. He’s isolating while continuing to work from the White House and taking Pfizer Inc.’s antiviral pill Paxlovid, a standard treatment for higher-risk patients. His wife said he was doing fine.

The different therapies reflect the evolving course of the virus and medical countermeasures against it. Back when Trump got sick there were no vaccines or FDA-authorized pills against the coronavirus. Earlier versions spreading at the time were associated with higher rates of severe complications.

“Trump was unvaccinated, and that was in the pre-vaccine era,” says infectious disease specialist Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Security.

The omicron subvariants spreading now, such as BA.5, are highly infectious but have tended to cause milder infections with significantly lower death rates.

In addition, Biden has received four vaccine doses and is in generally good health for his age, 79. The five-day course of Paxlovid has become the go-to treatment for keeping high-risk patients out of the hospital, despite reports that some occasionally experience a temporary rebound in symptoms or positive test results. Anthony Fauci, Biden’s 81-year-old chief medical adviser, experienced a resumption of Covid symptoms after receiving Paxlovid and eventually recovered.

Meanwhile, dexamethasone is mainly used in seriously ill hospitalized patients. Remdesivir is still widely used in the hospital and has also been authorized for outpatient treatment.

In theory, Biden could also get Eli Lilly & Co.’s bebtelovimab, a monoclonal antibody that retains activity against subvariants such as BA.5. However, the data backing it in combination with Paxlovid are limited, and the combo might be “of marginal benefit” in someone like Biden who has been extensively vaccinated, Adalja says.

With Covid, like other respiratory viruses, “the key thing is to be treated early,” says Mohammad Mahdee Sobhanie, an infectious disease physician at Ohio State University Wexner Medical Center.

People like Biden who are well vaccinated and get diagnosed and treated promptly, “are going to have a much better chance at avoiding hospitalizations and other severe complications,” he says.

This article was provided by Bloomberg News.