On Friday, the Norwegian Medicines Agency (NOMA) issued a statement saying that "common adverse reactions may have contributed to a severe course in elderly people who are frail".
Amid reports that a total of 33 people aged over 75 had died after being given a jab, NOMA played down safety concerns on Monday and said it was not “alarmed”.
It also said that claims by Pfizer/BioNTech that Norway had changed its advice to consider excluding the terminally ill from receiving the vaccine were incorrect.
Steinar Madsen, the medical director at NOMA, told Bloomberg that he was “not alarmed” by the deaths.
“Clearly, COVID-19 is far more dangerous to most patients than vaccination,” he said.
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“All of these patients have had serious underlying illnesses. We can’t say that people die from the vaccine. We can say that it may be coincidental.
“It is difficult to prove that it’s the vaccine which is the direct cause.”
Bloomberg reported that only the Pfizer-BioNTech vaccine was being used in the country by Friday and both companies were looking into what happened.
NOMA’s investigation of 13 of the deaths found that common adverse reactions to mRNA vaccines, including fever, nausea and diarrhoea, could have contributed to death in some frail patients, the British Medical Journal (BMJ) had said.
Doctors are still giving out doses in Norway but “extra evaluation of very sick people” with underlying conditions that could be worsened by a bad reaction should be carried out, Madsen has said.
The safety of vaccines is garnering global public attention after drugmakers developed the shots breakneck speed to curb a pandemic that has killed more than two million people.
US and European vaccine developers have pledged to uphold the scientific standards their immunisations will be held against in the race to contain the virus.
Stephen Evans, professor of pharmacoepidemiology at the London School of Hygiene and Tropical Medicine, also stressed there is “no evidence that any link between vaccination and death in these vulnerable patients is a causal one”.
Pfizer told the BMJ: “Pfizer and BioNTech are aware of reported deaths following administration of BNT162b2. We are working with NOMA to gather all the relevant information.
“Norwegian authorities have prioritised the immunisation of residents in nursing homes, most of whom are very elderly with underlying medical conditions and some of whom are terminally ill.
“NOMA confirm the number of incidents so far is not alarming, and in line with expectations.
“All reported deaths will be thoroughly evaluated by NOMA to determine if these incidents are related to the vaccine.
“The Norwegian government will also consider adjusting their vaccination instructions to take the patients’ health into more consideration.
“Our immediate thoughts are with the bereaved families.”
During Pfizer-BioNTech’s vaccine trials, which involved more than 43,000 participants, the companies found the “incidence of serious adverse events was low and was similar in the vaccine and placebo groups”.
A total of 59% of people aged 16 to 55 who were given the vaccine reported fatigue and 52% said they developed headache – both described as “systemic events”. In the placebo group 23% and 24% of people reported the same symptoms, respectively.
More “severe systemic events” were reported by less than 2% of vaccine recipients, except for 3.8% recording a headache and 2% saying they had a fever after the second dose.
Among four “serious adverse events” recorded from the vaccine group was an instance of abnormal lymph nodes in one participant’s armpit and an abnormal heart rhythm.
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