Norway’s Covid-19 vaccination program drew international scrutiny when it warned that giving shots to the very old and terminally ill may be risky, after a number of elderly nursing-home residents died a short time after receiving them.

The warning came as governments try to dispel vaccine skepticism, with health authorities on high alert for potential side effects from the shots, which have been developed in record time. This week, Norway moved to calm some of the anxiety, saying there’s no evidence of a direct link between the deaths and the vaccine, from Pfizer and BioNTech.

Norway, like other countries, has prioritized the immunization of nursing-home residents. Those who died were 75 or older and included terminally ill patients anticipated to have only weeks or months to live. An average of 400 people die each week in nursing homes and long-term care facilities, according to the Norwegian Medicines Agency.

Many people who’ve received the first inoculations have experienced fever, headache and pain at the site of the injection—all relatively common reactions and not generally serious. Norwegian officials said they couldn’t rule out that these reactions could potentially be life-threatening in patients with severe underlying health problems.

Germany has also seen several cases of elderly people dying shortly after vaccination. The deaths were probably due to the patients’ underlying diseases, not the inoculation, according to a report by the Paul Ehrlich Institute. Finland has recommended against systematic vaccinations of terminally ill patients whose active treatment has been stopped as common side-effects such as temporary fever can weaken their condition.

The reactions aren’t expected to be of significance in the vast majority of people. Millions of doses of the Pfizer-BioNTech vaccine have been administered in the U.S., U.K. and some other countries with no deaths reported due to the vaccine, according to Abrar Chughtai, a lecturer in the School of Public Health and Community Medicine at the University of New South Wales.

A Europe-wide safety report on the Pfizer-BioNTech vaccine is due to be published at the end of January, and should shed more light on the matter.