This week, COVID-19 headlines were split between cautious optimism and abject despair.

On the positive side, Monday morning brought us a scrap of hope — claims from Pfizer and BioNTech that their vaccine candidate was highly effective. Their tests so far showed that it has an efficacy of about 90 percent, though that number could change with time. And before we break out the bubbly, there are still plenty of caveats to the news.

Among the downer highlights: the full data hasn’t been released yet, and this happened in a clinical trial where conditions were more controlled than they will be in the real world. It has to be delivered in two doses, weeks apart, and it’s more fragile than frost on a sunny morning — it has to be stored at temperatures of -75 degrees Celsius (-103 degrees Fahrenheit), creating a logistical nightmare for facilities ill-equipped to stock something that frigid.

Put all those asides aside, and the vaccine news is still a spark of joy in a dark time. By next week, the companies claim that they should have enough data to start building their case for emergency authorization from the FDA. That’s a pretty exciting mile marker to look forward to, even if there’s still a long way to go before we get to a vaccine.

Meanwhile, the bad news was building. Here in the US, cases hit record highs, with an average of 134,078 cases per day over the past week, according to The New York Times. The surge in cases is overwhelming emergency rooms and ICUs across the country. Deaths are on the rise. Again. States are ordering lockdowns. Again.

Healthcare workers, already exhausted, dread what comes next. “The wave hasn’t even crashed down on us yet,” Eli Perencevich, an infectious-disease doctor at the University of Iowa, told The Atlantic’s Ed Yong. “It keeps rising and rising, and we’re all running on fear. The health-care system in Iowa is going to collapse, no question.”

Skyrocketing caseloads and healthcare systems teetering on the brink of collapse mean that the US has a lot of work to do to get through the next stage of this pandemic. It’s no longer just about flattening the curve. We’ve got a cliff to conquer.

We also know that the work will be worth it if we can save lives. As The Verge’s Nicole Wetsman wrote this week, “The light is still months away, but it’s there. We only have to make sure as many people as possible can get to it.”

Here’s what else we were watching this week.

Research

New Type of Test May Better Discern Immunity to the Coronavirus

Antibodies aren’t the only kind of immune cell in the body. T cells can also fight viruses. A company has come up with a blood test to detect these cells, which would be exciting. Caveat: the data of the test has not been reviewed by other researchers.

(Apoorva Mandivalli/NYT)

New Science Suggests How to Shorten Quarantine

An early study found that taking two COVID tests could let people stick to an eight-day quarantine instead of a 14-day quarantine. It’s an intriguing idea, but for it to really work, testing would have to be widely available. Another caveat here: This study has not been reviewed by other researchers.

(Roxanne Khamsi/Elemental)

We helped a New York sewage plant check poop for the coronavirus

This is a fun one. We sent a video team to a sewage plant to get a closer look at how wastewater facilities are helping communities track the spread of coronavirus.

(Nicole Wetsman/The Verge)

Development

Pfizer’s announcement shows the promise of gene-based vaccines

The vaccine results this week were a big boost for mRNA-based vaccines in general. If this one succeeds, we could see more like it in the future.

(Nicole Wetsman/The Verge)

Pfizer’s ultra-cold vaccine, a ‘very complex’ distribution plan, and an exploding head emoji

CNN has a really interesting look into some of the planning going on at a state level to handle a potential vaccine that needs to be kept much colder than ice cold.

(Elizabeth Cohen, John Bonifield and Sierra Jenkins/CNN)

‘We’re being left behind’: Rural hospitals can’t afford ultra-cold freezers to store the leading Covid-19 vaccine

The CDC is not recommending that hospitals stock up on ultra-cold freezers, but some wealthy hospitals are doing it anyway. Rural hospitals with fewer resources would like to do the same, but can’t afford the equipment, even as supplies dwindle.

(Olivia Goldhill/STAT)

Russia’s claim of a successful COVID-19 vaccine doesn’t pass the ‘smell test,’ critics say

After Pfizer and BioNTech made their announcement, Russia also announced that it had results on its ‘Sputnik V’ vaccine. Experts are skeptical of both the timing and the fact that the results only looked at 20 COVID-19 cases, compared to Pfizer and BioNTech’s 94.

(Jon Cohen/Science)

Pfizer says placebo patients will eventually get its Covid-19 vaccine. The question of when is complicated

During clinical trials some people get the treatment being tested, and others get a placebo. The question now is what happens to the people who got a placebo once a vaccine is authorized — and when can they get a working vaccine?

(Matthew Herper/STAT)

Perspectives

“They don’t want to be watched over or babysat or told what to do, and I can understand that, but I’d like to believe we’re still capable of making a communal sacrifice. Stay home. Be reasonable. Wear a mask.”

—Tom Dean, a doctor in South Dakota on the dire situation in his home. As told to Eli Saslow, The Washington Post

“My grandfather’s death, six months into the pandemic, is more than a tragedy. His fate is as political as it is biological. And I am furious.”

—From COVID took my grandfather. But it wasn’t what killed him by Sarah Jones in The Cut

More than numbers

To the more than 53,492,701 people worldwide who have tested positive, may your road to recovery be smooth.

To the families and friends of the 1,304,864 people who have died worldwide — 244,364 of those in the US — your loved ones are not forgotten.

Stay safe, everyone.