Temple University Hospital System’s offer of COVID-19 shots to 10,000 older and medically at-risk patients prompted a low response rate — just 15% — from the people who should be most concerned about getting the virus.

But after those initial invitations to register through TempleHealth, its online patient portal, the hospital system followed up with phone calls. The acceptance rate jumped to about 80%.

“We knew this was going to be a lot of manual phone calls in our population,” said Tony Reed, chief medical officer at Temple University Health System. “We’re afraid that the people who need it aren’t going to get it if we don’t make it a personal touch.”

Hospitals, which began inoculating patients within the last few weeks after getting their staff vaccinated, are key to Philadelphia’s vaccine distribution process. In recent weeks, city hospitals have vaccinated thousands of adults 75 and older, and adults with high-risk health conditions that make them particularly vulnerable to COVID-19. But many others in these eligible groups have not responded to invitations to register through online health portals — no surprise to many who have looked at how patients use such systems.

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Doctors extol the advantages of the portals, which allow patients a one-stop site for communication with physicians, prescription renewals, test results, and other health information. They are a ready-made vehicle for hospitals to set up vaccine appointments, something other vaccine providers have struggled with.

But as a 2020 study and other research has found, the patients that could most benefit from them are least likely to use them. They not only require internet access and savvy, but patients need to register in advance to participate, something that those who didn’t grow up in the digital age may be reluctant to do even if they are able.

Steven Sivak, president and chief medical officer, Einstein Physicians Philadelphia, said it’s no surprise that scheduling through the portals didn’t lead to robust participation.

“That’s predictable for a couple reasons,” Sivak said. “A lot of our patients don’t have access to the portal. Even for our patients that do have access to the portal, we’ve noticed messages that get sent out don’t get recognized.”

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Einstein skipped the portal entirely, he said. Instead, doctors called patients directly, and if the patients agreed to be vaccinated, shared their information with a call center that contacted them to schedule an appointment. Sivak didn’t have the exact number of Einstein patients eligible for vaccination but said it was several thousand. Of those reached by phone, about 70% are scheduled to receive shots.

About 8,200 Temple patients have either received shots or are now scheduled for injections out of about 10,000 invited between Jan. 25 and Feb. 16. The University of Pennsylvania’s clinics are fully booked, dispensing up to 8,000 shots a week to patients who have been signed up by email or phone.

The hospitals’ experiences could provide lessons for other vaccine providers, such as state and local governments, particularly as they attempt to contact seniors who are among those eligible for the shots. Relying on online registration in the vaccination process has frustrated many residents’ attempts at getting the shot in Pennsylvania and elsewhere.

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Reaching people who could most benefit from vaccination promises to be an ongoing challenge, and even phone calls aren’t foolproof, Sivak said. Doctors regularly report having a hard time reaching patients under normal circumstances. They just don’t answer the phone, he said.

“People don’t pick up because they don’t recognize the number,” he said. “We find that it’s more challenging than we would like reaching patients.”

Of the minority of people Einstein tried calling but didn’t schedule for shots, Sivak said, most couldn’t be reached by phone. The call center’s policy is to try reaching people with three separate attempts, and then move on to other patients.

The University of Pennsylvania, too, has been calling patients since Jan. 18, with a focus on those who don’t use the hospital’s online patient portal. The hospital is working on increasing its phone scheduling capacity and may also send letters or text messages to patients who can’t be reached online, said Deborah Driscoll, senior vice president for the clinical practices.

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The hospital has contacted more than 42,000 patients, but a large portion of its emails are going unanswered, in part because some patients don’t have accounts for the system’s online portal. About 35% of people contacted have scheduled appointments. But of those reached by phone, half registered for vaccination.

“To begin with, I think that’s a really respectable response rate,” said Driscoll. “The patients that are scheduling their appointments are just thrilled to be getting invitations, and they’re so excited they often show up for their appointment an hour early.”

A lack of internet access isn’t the only obstacle to people who need the vaccine: Patients are also reporting hesitancy.

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Those wary of the vaccine, hospital representatives said, often want more information or wonder if they should wait to get the shot, which has been shown in clinical trials to be very effective, does not contain live virus, and cannot give anyone COVID-19.

“Some of our patients, when we’ve called them, say that they’re not ready to schedule yet, they want to talk to their health-care provider,” Driscoll said. “They just want to know, Is this the right time for me to receive the vaccine?”

Jefferson Health — which is offering appointments through its patient portal but has a task force working on patient outreach — also has seen that personal conversations help overcome hesitancy.

“Once our physicians and staff have conversations with patients who are hesitant to get the vaccine, many of them are convinced after sharing our own personal vaccination stories or addressing a more specific concern,” said spokesperson Brandon Lausch.

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That makes even more sense when you consider, as Temple’s Reed noted, that the people eligible for vaccinations now are more likely than younger or healthier people to have regular interaction with their doctors.

Convenient and efficient as portals can be for patients who use and trust them, the experience so far suggests personal contact will continue to be essential in vaccinating more people, including those who may rarely or never see a doctor.

“At some point we need to consider,” Reed said, “whether we’re working with the population just of people who seek care.”