Rob Stein

Updated Oct. 14, 12:45 p.m. ET

If you got the Johnson & Johnson vaccine as your first COVID-19 shot, a booster dose of either the Moderna or Pfizer-BioNTech vaccine apparently could produce a stronger immune response than a second dose of J&J's vaccine. That's the finding of a highly anticipated study released Wednesday.

Carlene Knight's vision was so bad that she couldn't even maneuver around the call center where she works using her cane.

"I was bumping into the cubicles and really scaring people that were sitting at them," says Knight, who was born with a rare genetic eye disease.

But that's changed as a result of volunteering for a landmark medical experiment. Her vision has improved enough for her to make out doorways, navigate hallways, spot objects and even see colors.

"It's nice. I don't scare people and I don't have as many bruises on my body," Knight says, laughing.

Americans may be able to breathe a tentative sigh of relief soon, according to researchers studying the trajectory of the pandemic.

The delta surge appears to be peaking nationally, and cases and deaths will likely decline steadily now through the spring without a significant winter surge, according to a new analysis shared with NPR by a consortium of researchers advising the Centers for Disease Control and Prevention.

A head-to-head comparison of all three COVID-19 vaccines found Moderna is holding up better than Pfizer and the Johnson & Johnson vaccine provides the weakest protection.

But the researchers stressed that all three vaccines are still providing strong protection against people getting so sick that they end up in the hospital.

Like millions of others, Kathleen Hipps thought she was safe from COVID-19 after she got two shots of the Moderna vaccine last spring. So she figured she just had a summer cold when she got the sniffles in July. But then she opened some Vick's VapoRub.

"Anyone who's ever smelled Vick's VapoRub knows how pungent of a smell it is. And I couldn't smell it. And that's how I knew I had COVID," says Hipps, 40, a Los Angeles lawyer who has two young sons.

There's more potentially worrisome news for vaccinated people: In very rare cases, people experiencing breakthrough infections may be at risk for long-COVID symptoms.

That's according to a small new study of fully vaccinated health care workers in Israel, published Wednesday in The New England Journal of Medicine.

This story has been updated throughout to reflect new research.

New data on the delta variant is coming in, and it's not looking good. The currently authorized vaccines are still very protective, especially against hospitalization and death. But when it comes to getting an asymptomatic or mild case of COVID-19, they may not be quite as protective as they were against earlier strains.

Patrick Doherty had always been very active. He trekked the Himalayas and hiked trails in Spain.

But about a year and a half ago, he noticed pins and needles in his fingers and toes. His feet got cold. And then he started getting out of breath any time he walked his dog up the hills of County Donegal in Ireland where he lives.

"I noticed on some of the larger hill climbs I was getting a bit breathless," says Doherty, 65. "So I realized something was wrong."

The dangerous Delta variant of the coronavirus is spreading so quickly in the United States that it's likely the mutant strain will become predominant in the nation within weeks, according to federal health officials and a new analysis.

The U.S. is banning the importation of dogs from more than 100 countries for at least a year because of a sharp increase in the number of puppies imported into the country with fraudulent rabies vaccination certificates.

"We're doing this to make sure that we protect the health and safety of dogs that are imported into the United States, as well as protect the public's health," Dr. Emily Pieracci of the Centers for Disease Control and Prevention tells NPR.

As the pandemic calms in the U.S., a growing number of states have started scaling back how often they update their dashboards tracking what's happening with the virus.

The moves are sparking alarm among many public health experts.