Let’s keep the content upbeat on a holiday. Surely this site can manage a bad news/good news ratio in posts about the COVID-19 epidemic of no worse than 1,000 to one.

2,000 to one, tops.

The first piece of good news has to do with antibodies. One of the most consequential mysteries about the disease right now is whether getting sick and recovering means that you’re immune afterward (at least for awhile). Scientists are still working to nail that down, but there’s a preliminary question before we even reach the immunity question. Is everyone who’s getting sick actually producing antibodies? There were some ominous studies out of Asia, remember, that suggested some people were being reinfected or the virus was “reactivating” inside them after they recovered. That meant either that they were producing antibodies and the antibodies weren’t working to stave off new infections or they weren’t producing antibodies at all. Bad, bad news either way.

Researchers in New York City have been running tests. Results: Yes, virtually everyone who’s being infected is producing antibodies, even people with mild cases. You may not need to get very sick from COVID to beat it.

3) The majority of these donors were mild cases. Now, almost all PCR-confirmed donors had antibodies, while the majority of the suspected COVID19 individuals did not. This tells us two things: a) the assay works and b) many people who think they had COVID19 might not have had it. pic.twitter.com/N86y2K9DRN

— Florian Krammer (@florian_krammer) May 6, 2020

99.5 percent of people with confirmed infections had antibodies in their blood later — although in some cases it took three weeks or more after they began showing symptoms for the antibodies to be detectable. As for the all-important question of whether antibodies provide immunity, the jury’s still out. But early results are looking good:

In Dr. Krammer’s previous work, to be published in the journal Nature Medicine, his team tested whether the antibodies have neutralizing power. The researchers found that in about a dozen people, including some who had mild symptoms, the level of antibodies in the blood corresponded to the level of neutralizing activity.

So everyone who makes antibodies is likely to have some immunity to the virus, Dr. Krammer said: “I’m fairly confident about this.”

Another part of the same study found that the “reinfected” patients in Asia probably weren’t reinfected at all. People who were still testing positive weeks after recovery likely didn’t have any live virus left in their system; what was being picked up in testing were the remnants of dead virus whose genome was still present. Researchers in South Korea who conducted a separate study came to that conclusion as well.

The second piece of good news has to do with testing. Remember a few weeks ago when Deborah Birx said that we needed a “breakthrough” in order to scale up testing dramatically? She was referring to the need for an antigen test. Right now most coronavirus testing is PCR testing, where you get your nose and swabbed and then the sample is sent away to the lab. Results come back in a day … or two, or longer. Abbott improved on that in late March with a test that could be performed on portable machines, with results in as soon as five minutes. But at the time they were projecting producing “only” up to 50,000 tests a day that way, a fraction of what the country needs. Also, if I’m understanding the science correctly, their test looked for direct evidence of the virus in the form of its genome. An antigen test can detect the virus’s presence based on circumstantial evidence, like proteins attached to it.

Antigen tests would be simpler than PCR lab tests, cheaper, capable of producing results within 15 minutes or so right in a doctor’s office, and scalable. And now they’re here:

The Food and Drug Administration has granted emergency-use authorization to Quidel Corp. for the first antigen test for the Covid-19 virus—a step that could escalate the nation’s ability to test for the disease…

San Diego-based Quidel, which specializes in tests for flu, strep and other infectious diseases, already has placed about 36,000 test-analyzer instruments around the U.S. in places like hospital labs, emergency departments and doctors’ offices.

“We are ramping up manufacturing to go from 200,000 tests next week (week of May 11) to more than a million a week within several weeks,” said Douglas Bryant, Quidel’s chief executive.

We’re up to around 300,000 tests per day in the U.S. right now. If Quidel’s true to its word, they could singlehandedly increase capacity by another 50 percent rapidly. Other companies will doubtless follow soon with antigen tests of their own, further boosting capacity. Technology is gradually solving our testing shortfall for us. That said, there are wrinkles: Quidel’s test is “only” 85 percent accurate right now, which means patients will probably also have to be tested via labs in the short term while accuracy improves. There’s also a question of whether doctors will want infected people coming through their offices in order to take the antigen test. Scott Gottlieb told WaPo that if the CDC’s guidelines are too burdensome, requiring GPs to don full protective gear to perform the test, some physicians might decline to do it. We’ll see.

The third bit of good news is straightforward. Researchers in Hong Kong are tracking the results of how different drugs are performing in treating COVID patients and think they’ve hit on something.

Of those participating, 86 patients were given a two-week course of three medicines: interferon beta-1b, a drug used to treat multiple sclerosis; HIV drugs lopinavir-ritonavir; and ribavirin, used to treat hepatitis.

A randomly-assigned control group of 41 people was just given the lopinavir-ritonavir combination…

They found that those taking all three medicines were able to clear the coronavirus in seven days on average (between five and 11 days) — “significantly” shorter than the 12-day average for the control group.

Those on the three-drug regimen also saw a complete alleviation of their symptoms in an average of four days, compared to eight for the control group.

That’s the same sort of benefit that was seen from remdesivir in NIH’s recent clinical trial. But there are wrinkles here too. No one received a placebo so there’s no way to know how effective any of the individual drugs involved were relative to no drug at all. And the study was “open label,” so doctors and patients knew which drugs were being used. The promise of interferon is especially interesting, though, since that drug was identified years ago by scientists as potentially effective against COVID-19’s cousin, SARS. In this new study, researchers tested a small number of patients on lopinavir-ritonavir only and then another group of patients on a combination of lopinavir-ritonavir and ribavirin and found that both cleared the virus in equal lengths of time. Only the group that received interferon along with the other drugs cleared it more quickly. Hmmmm.

If you missed it on Thursday, here’s an extra piece of good news for you. I’ll leave you with Scott Gottlieb sounding excited about the new antigen test.