Unlike the U.S. where anti-vaccine fringe groups have fueled resistance to COVID-19 shots, Hong Kong is facing a different challenge. Most of the city’s older residents are reluctant to get inoculated, and some point to an unlikely source for the hesitancy: their doctors.

Almost half a year into the territory’s vaccination program with freely available shots, older people are still staying away, due in part to advice from ultracautious doctors to defer vaccination if they have chronic conditions not yet under control. The physicians appear to have taken their cue from a mid-March government recommendation that came after several post-vaccination deaths and cases of adverse reactions were reported in the early days of the rollout, though studies found no links between the fatalities and the shots.

Thanks in part to such doubts and fears, Hong Kong has one of the lowest vaccination rates among developed economies, hampering efforts to reopen borders and spur a recovery from the pandemic. Among people age 65 and above, just an estimated 28% have received at least one dose, according to a Bloomberg analysis of government data, compared with 90% in the U.S. and 87% in Japan. For those above the age of 80 in Hong Kong, the number shrinks to 8%.