Massachusetts, the first US state to launch a coronavirus contact-tracing programme, quickly ran into a problem: People are not answering their phones after being conditioned by years of spam calls.
About half of the 10,000 calls a day made by a team of 1,600 contact tracers went unanswered, said operations director John Welch of Partners In Health at a briefing last week. The non-profit healthcare organisation is partnering Massachusetts in the contact-tracing effort.
Officials have since worked with telcos to ensure the calls they make will be identified as coming from the "MA COVID Team", but the hiccup underscores the logistical challenges of the country's reliance on an army of human contact tracers.
Experts have touted the ability to trace the contacts of Covid-19 patients and warn them of their exposure, along with readily available tests and isolating the sick, as key to safely reopening America's coronavirus-closed economy.
But while tech giants are racing to develop and roll out apps to facilitate contact tracing, the American public and privacy advocates remain wary of them.
In a report last month, health security experts from the Johns Hopkins University (JHU) and the Association of State and Territorial Health Officials concluded that the United States would find it difficult to use technology-heavy contact-tracing methods owing to privacy protections.
"The US won't be able to replicate a contact-tracing effort like the one in South Korea, for example, which can use medical records, phone GPS records, credit card transactions, and closed-circuit TV," said lead report author Crystal Watson, a Johns Hopkins Centre for Health Security senior scholar.
However, the US could adopt the approaches of New Zealand and Iceland, which use traditional contact-tracing measures supplemented with complementary technology, the report added.
"A contact-tracing effort of this unprecedented scale and of this critical and historical importance to the functioning and reopening of society has never before been envisioned or required," said the report.
"Our current core public health capacity is woefully insufficient to undertake such a mammoth task."
An additional 100,000 contact tracers and some US$3.6 billion (S$5.1 billion) are needed across the nation to start with, the report estimated.
California aims to hire 20,000 contact tracers, while New York is looking at hiring up to 17,000.
Contact tracers may encounter ethically tricky situations, according to the free JHU training course launched last week that New York tracers are required to complete.
For instance, a contact could be an undocumented worker, unwilling to be quarantined because not working means not getting paid, said JHU epidemiologist and course convenor Emily Gurley.
In that scenario, tracers do not have the right to disclose that private information to anyone else, including the police and the immigration authorities.
Meanwhile, Google and Apple are teaming up to build apps that can use Bluetooth to track people's exposure to others with Covid-19.
While South Korea has embraced such apps, their success in other countries such as Singapore has been more limited.
Singapore's TraceTogether national contact-tracing app has been downloaded by 25 per cent of the population, short of the 75 per cent rate needed for it to be effective.
In America, only 41 per cent of adults say they would take part in mobile device tracking, a Reuters Ipsos poll late last month found.
Currently, tech companies and public health officials are tussling over the amount of user data to reveal to the authorities, The Washington Post reported last Friday.
The software will tell users if they might have come into contact with a Covid-19 patient but will not tell health departments where those meetings happened, which officials say is of no help to state contact-tracing programmes.
Said JHU's Dr Watson: "There has to be a balance between personal privacy and getting health departments the information they need to act quickly.
"The Google and Apple partnership is promising, but it's unclear how public health officials will be able to use that information. I don't think we've struck that right balance yet with the technologies that are out there."