The scary thing finally happened: someone caught the coronavirus twice and got sicker the second time around. A 25-year-old man in Nevada got COVID-19 in March, got better in April, and got sick again in May. He had worse symptoms on the second bout, bad enough that he had to be hospitalized.

Three other cases of confirmed reinfection were also reported this week: one in Hong Kong (the first documented case) and two in Europe. These don’t necessarily make me any more worried about our vaccine prospects, though, and they don’t mean the pandemic will go on forever. We have four documented cases of reinfection. But that’s out of the 24 million cases of this disease so far, and rare shit happens. Most experts expected that we’d see at least a few.

For months, there have been occasional, anecdotal reports of people testing positive for COVID-19 twice. None of those were proven to be reinfections. For most of those people, the second test probably picked up residual, dead virus that was still floating around in people’s noses and throats after their first infection.

In these reinfection cases, though, researchers actually analyzed the virus from the first time the people got sick and compared it to the virus from the second time they got sick. In each case, the two viruses had slightly different genetic sequences, showing that the second positive tests weren’t just leftover virus.

Here’s the other important thing: in the Hong Kong case, the second infection caused no symptoms at all. That means his immune system probably recognized the virus from the first infection and kept it in check. We don’t know why that didn’t happen for the man in Nevada. He wasn’t tested for antibodies the first time he got sick, so it’s possible that he just didn’t make any. That’s the more encouraging option. The other possibility is that he had antibodies, but they made the infection worse (it happens with other viruses, like dengue).

Case studies only answer one question: can you catch COVID-19 twice? But that’s about all they do. Mostly, they raise questions rather than answer them. How common is reinfection? How infectious are people if they get sick a second time? Are people who don’t generate many antibodies the first time they contract the virus the only people who can catch it again?

The pandemic feels like it’s gone on for 1 million years, but in a more real way, the coronavirus has only existed in the human population for about nine months. Scientists have learned so much, so fast, but there’s still a long way to go. The human immune system is weird and confusing, and it’s squaring off against a new, never-before-seen virus. It’s going to take time to understand what’s happening.

Oh, and the other thing — this is a reminder that even if you’ve already had COVID-19, you still need to be careful.

Here’s what else happened this week.

Research

Biogen conference likely led to 20,000 COVID-19 cases in Boston area, researchers say

In February, before we knew the extent of COVID-19 in the US, 175 biotech executives gathered for a conference in Boston. At that meeting, the virus spread from attendee to attendee — and the outbreak eventually led to tens of thousands of cases all around the world, according to one analysis. The study shows that even a small gathering can have wide-ranging, devastating ripple effects on the course of the pandemic. (Jonathan Saltzman / The Boston Globe)

Four scenarios on how we might develop immunity to Covid-19

Months into the pandemic, scientists still aren’t sure what happens to our immune systems after we recover from COVID-19. Most researchers think people will have some protection against the virus, but they still don’t know what that protection will look like. Stat News broke down some of the possibilities. (Helen Branswell / Stat News)

Development

FDA authorizes Abbott’s fast $5 COVID-19 test

The Food and Drug Administration authorized a $5, 15-minute COVID-19 test that works like a pregnancy test: a nasal swab gets inserted into the bottom of a test card and a colored line appears if the sample is positive for the coronavirus. It’s a big step forward, experts say. (Nicole Wetsman / The Verge)

Moderna Says Covid-19 Vaccine Shows Signs of Working in Older Adults

The drug company ran a small study testing their COVID-19 vaccine candidate in people over the age of 56, and it found they produced the same types of immune response that younger people did. This doesn’t mean that they’re protected from infection with the coronavirus — we still need data from much bigger trials to prove that. But it is a promising sign: older peoples’ immune systems are weaker than younger peoples’, and vaccines sometimes don’t work as well for them. (Peter Loftus / The Wall Street Journal)

What if the First Coronavirus Vaccines Aren’t the Best?

While companies like Moderna and Pfizer are racing to collect data on their COVID-19 vaccine candidates by the end of the year, dozens of other companies are moving at a slower pace. They’re building their vaccines using different types of technology than the ones at the head of the pack, and some researchers think they may have more staying power. “The first vaccines may not be the most effective,” Ted Ross, the director of the Center for Vaccines and Immunology at the University of Georgia, told The New York Times. (Carl Zimmer / The New York Times)

Perspectives

What happened in Room 10?

Reporter Katie Engelhart investigated the deadly COVID-19 outbreak at the Life Care Center of Kirkland, Washington, the first virus hotspot in the United States. Something clearly went wrong — but who was to blame?

Later, the story of the Life Care outbreak would be flattened by the ubiquitous metaphors of pandemic. People would say that COVID-19 hit like a bomb, or an earthquake, or a tidal wave. They would say it spread like wildfire. But inside the facility, it felt more like a spectral haunting. A nurse named Chelsey Earnest said that fighting COVID was like “chasing the devil.”

(Katie Engelhart / California Sunday)

‘We’re Living The News’: Student Journalists Are Owning The College Reopening Story

On college campuses around the country, student journalists are tirelessly documenting reopening plans and COVID-19 outbreaks. It takes a toll. “We are scared because not only is this news that we’re writing about for other people to hear, we’re also hearing about it ourselves for the first time usually when we’re writing about it,” Brandon Standley, managing editor at UNC’s The Daily Tar Heel, told NPR.

(Elissa Nadworny and Lauren Migaki / NPR)

More than numbers

To the more than 24,775,245 people worldwide who have tested positive, may your road to recovery be smooth.

To the families and friends of the 837,908 people who have died worldwide — 181,779 of those in the US — your loved ones are not forgotten.

Stay safe, everyone.

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