This episode was filmed on June 16, 2020.

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COVID-19 pandemic, check the playlist linked in the description. [♪ INTRO]. While most patients with COVID-19 pull through, worldwide, the pandemic has caused more than 435,000 deaths. So, doctors have been trying pretty much everything they can think of to lower the disease's fatality rate.

Unfortunately, even our most promising drug candidates have turned out to be ineffective. But now, we have another option. According to an announcement made by the researchers running a trial in the UK called the RECOVERY trial on June 16th, there's a drug that helps save people with serious infections.

And it's one you probably have not heard about in relation to the pandemic: dexamethasone. While everyone has been fighting about hydroxychloroquine and remdesivir, the researchers in this trial have also been testing other commonly used drugs, including dexamethasone. It's what doctors call a corticosteroid—so, a steroid that resembles the natural hormone cortisol.

You've probably heard of cortisol in the context of stress, because it helps prepare your body to react to danger. But one of the ways it does that is by ramping down the immune system. In other words, cortisol — and drugs that mimic it like dexamethasone — help reduce inflammation.

And that's why those designing the RECOVERY trial thought dexamethasone might help people with severe COVID infections. People who are hospitalized with COVID-19 are generally experiencing extreme immune reactions and a lot of inflammation. Essentially, their immune systems are trying so hard to kill the virus that they end up damaging healthy tissues—which can be fatal.

Medications that can reel in the immune system a bit may be able to help prevent that damage, and save lives. And that seems to be exactly what dexamethasone does. In the trial, researchers gave a little over 2100 patients dexamethasone for 10 days, while another 4300 or so got the usual hospital care.

And when they compared the final outcomes for those patients, the ones that received the drug had a higher chance of surviving —but only if they were sick enough to need oxygen or a ventilator. It had no effect on the 13% of patients that didn't need that kind of aid, probably because their immune systems weren't overreacting as much. In fact, early on in an infection, or in people who don't have severe symptoms, steroids like dexamethasone could be harmful, as they reduce the body's natural ability to fight the virus.

For those in the trial that were really sick, though, dexamethasone reduced deaths. It lowered them by one-third in the sickest group —those that were put on ventilators. And it cut mortality by one-fifth in those who needed supplemental oxygen.

Doctors are already buzzing about these results, as this is the first drug we know of that seems to help those who need it most. But, we would be remiss if we didn't point out that these results are very preliminary. The team running the RECOVERY trial hasn't even released the actual data yet!

So, we shouldn't get too excited until experts have a chance to examine the results. Still, the findings are promising enough that the drug will likely be added to other ongoing trials. And frankly, it's kind of nice to have some good news to talk about.

It's been a long few months, what with lockdowns and school closings. And, sure, it helps to know that we're doing our part by staying in and such, but so far, the benefits have been pretty vague. Well, I have some more good news.

Thanks to two new papers, we have a much more concrete idea of how many lives have been saved by all of that work. And the numbers might be higher than you'd expect. Two papers published in Nature last week looked at the effects of distancing policies as a whole — things like stay-at-home orders and closing schools.

One of these papers used data from 11 countries in Europe to estimate how many people would have died from COVID-19 if lockdown measures hadn't been implemented. They based their model on the number of reported deaths. It's not a perfectly reliable metric, but it's better than using the reported number of cases, since in most places, not everyone who's had the virus has been tested.

Specifically, they wanted to look at one of the most important factors in how a disease spreads over time, with interventions: its effective reproduction number, or R. That's the number of people that, on average, are infected by each sick person over the course of their illness. You may have heard this referred to as R0, but that's only the basic reproduction number, which is how many people can be infected by a single person when everyone is vulnerable and there are no restrictions in place.

In the real world, R changes over time—like, thanks to social distancing recommendations that keep people separated. Based on early numbers, the researchers estimated the initial reproductive number for COVID-19 in Europe to be around four at the beginning of the pandemic. But by early May, after several weeks of different non-pharmaceutical interventions like stay-at-home orders and wearing masks, the effective reproduction number went down to between 0.44 to 0.82, depending on the country.

Which is huge, since an effective reproduction number less than one translates to fewer and fewer people contracting the disease. And that is how you contain an outbreak. Researchers also used their model to estimate roughly how many people would have died from COVID-19 without interventions.

Through early May, the number of reported deaths in just these 11 countries was about 130,000. Without restrictions, the team estimated that the number would have been over 3.2 million. The other Nature study looked at the effects of lockdowns on overall infection rates from six countries: China, South Korea, Italy,.

Iran, France, and the US. They based their model on confirmed infections, which, as they point out, is a bit complicated thanks to the different testing rates we mentioned earlier. But, they also point out the value of using multiple types of data to model the pandemic, since you can compare the models to learn more about the situation as a whole.

The researchers estimated that restrictions in these six countries may have prevented about 530 million infections. And that's only through the first week of April. So, yes — these lockdowns are not fun, for a lot of different reasons.

But the data suggest that they also saved millions of people's lives, and kept hundreds of millions more from getting sick. And when we're stuck at home now, or in the future, missing the way things used to be,. I think this knowledge will help a bit.

Thanks for watching this episode of SciShow News! And a special thank you to our President of Space Joshua Furman. We wouldn't be able to make episodes like this without Joshua and our other patrons on Patreon.

So we're really thankful we have such a wonderful community of supporters. If you're interested in joining that community and supporting what we do here at SciShow, you can learn more at Patreon.com/SciShow. [♪ OUTRO].