PASADENA, United States: It's official: America's COVID-19 immunisation campaign is stalling.
While vaccination programs are lagging badly in many countries - if they've begun at all - mass vaccine sites across the US are closing due to dwindling demand, leaving the authorities exploring new ways to reach people who haven't yet gotten a shot.
The national vaccination rate peaked around Apr 11, according to official data, and although 55 per cent of US adults now have had one or more doses, there's still a long way to go to achieve population immunity.
The people most eager to get their shots have, for the most part, already rolled up their sleeves and done so.
The challenge is reaching the rest.
In Texas, as in much of the country, vaccinations are in freefall. A huge federal site in Arlington, between Dallas and Fort Worth, shut its doors in mid-April because of insufficient numbers.
Two other federal sites, the NRG Stadium in Houston and Fair Park in Dallas, have ended their appointments system and now take walk-ups.
The NRG Stadium, seeking to ease the process, is now remaining open until nine o'clock in the evening rather than five, and vaccinating people in their cars.
Even so, that site is only running at half capacity.
"We have the capacity to see about 6,000 people and at one point we saw up to 7,000 people. And now, it's dropped to 2,500 on average. So that is a huge drop," said Martha Marquez, a spokeswoman for Harris County Public Health.
Authorities are considering more targeted approaches to reach people who are geographically isolated or find it hard to reach vaccine sites.
Five mobile vaccination centres are now crisscrossing those areas of the county with the highest number of positive cases.
"Next week, we'll be increasing to 10 clinics," Ashlei Dawson, the official in charge of one of the sites, told AFP, as she oversaw the training of new recruits.
Her own team had set up for the day at the public library in Pasadena, a mainly Hispanic suburb of Houston.
Members of the public were only trickling in, and by midday just 27 people had received injections.
One of them, 55-year-old Jose Herrera, said, "I didn't do it before because it was too far away." He said he was also concerned about side effects.
Dozens of supermarkets and pharmacies around the city are now advertising vaccinations.
But Herrera and his wife, Maria, were finally persuaded by their daughter, who works at the Pasadena library, to get theirs done.
Others are still in the "wait and see" camp.
Wyatt Gregg, a 31-year-old cowboy and rodeo coach from Borger, in the northwest of the state, told AFP he hadn't given the question much thought.
"Most of the time, I am outdoors and not around people. When I need to travel by plane, at the airport, everybody wears a mask."
The COVID-19 vaccines "are a new deal on the market - we don't have long-term test results", he added.
But while there has been considerable attention paid to so-called anti-vaxxers, the group is actually quite small, said vaccinologist Saad Omer, director of the Yale Institute for Global Health.
"Vaccine acceptance is on a spectrum," he said, and when people who are lukewarm to the idea of getting a shot encounter obstacles, they're less likely to push ahead.
"One way to deal with it is increase their demand," said Omer.
The other way, he added, is to make vaccination so easy and accessible that even people who are on the fence say, "'Okay, let's get it done.'"
Still, some population groups remain skeptical.
Among Republican voters, 29 per cent say they will never take the vaccine, compared to five per cent of Democrats and nine per cent of independents, according to a recent survey by the Kaiser Family Foundation.
White evangelicals are another increasingly important holdout group.
US Surgeon General Vivek Murthy on Friday promised a new initiative to help people get vaccines through their own doctors who, research shows, are often the most trusted messengers.
Omer said lessons could be drawn from the way Black physicians and healthcare organizations helped overcome mistrust among African Americans.
"If someone has to castigate (the white evangelicals), it should be a white evangelical person, not an outside person," he said, "a leader from the community who has the cachet to do that."