According to the findings of a small study, the Pfizer/BioNTech vaccine causes mostly mild or moderate side effects in 12–15-year old children considered vulnerable to COVID-19 infection

Vaccine patient and HCP

Side effects from the Pfizer/BioNTech vaccine in children aged between 12 and 15 years considered vulnerable to COVID-19 infection were mostly mild or moderate, a small study has suggested.

Researchers in Bristol looked at 27 children whose parents recorded any side effects after the jab.

Adverse reactions were either mild or moderate in all of the young people, except one who had ‘severe fatigue and severe discomfort combined with increased agitation’.

But experts said the small size and scope of the study does not allow for conclusions on rare side effects or inform the debate on vaccinating healthy younger teens.

Child jabs 

Currently, children aged between 12 and 15 years who are clinically vulnerable to COVID-19 or live with adults who are at increased risk of serious illness from the virus are eligible for a coronavirus vaccine.

There have been calls from some quarters to extend the roll-out to all healthy 12–15 year olds, especially as the return of schools is expected to lead to a rise in infections.

The Joint Committee on Vaccination and Immunisation has not given a recommendation to widen the roll-out to this age group, but the NHS in England is reportedly making preparations to enable it to proceed if there is a decision to do so.


All of the participants in the study were children with severe neurodisabilities, who tend to get recurrent respiratory infections and spend time in residential care.

Researchers said that one family reported a change in seizure type, but that this had resolved a week after the vaccine.

Effects in six of the children after a first dose included a mild rash, headache, diarrhoea, presumed sore throat, neck pain, difficulty sleeping, and low blood sugar.

But all of these had gone away within 72 hours, according to the study, which is due to be published in the Archives of Disease in Childhood.

Five of the children had effects including diarrhoea, vomiting, armpit swelling, and blisters around the mouth after the second dose.

The researchers said that fever was more common than in adult studies, with 13% of the children having a temperature greater than 38°C compared with 4% in people aged between 16 and 55 years.

Other recorded adverse events all resolved within a week, the study by scientists from the Department of Paediatric Immunology and Infectious Diseases at Bristol Royal Hospital for Children and the University of Bristol noted.

They said: ‘Numbers were small, but these data are especially important as they are representative of the children who are most likely to benefit from vaccination, and parents and clinicians may have concerns regarding an increased risk of unexpected events’.

Reassurance for parents 

Russell Viner, Professor of Adolescent Health at the UCL Institute of Child Health, said that the study ‘should reassure parents and doctors that there are no special precautions or issues with this vaccine in this small group of children’.

He added: ‘However, these data can tell us very little about rare side effects or about vaccinating healthy teenagers or those with common conditions such as asthma and diabetes. For that, we must await further data in the order of millions of doses’.

Dr David Elliman, Consultant Paediatrician at Great Ormond Street Hospital, said: ‘This is a small study, as the authors point out, and it is not explained how these patients were chosen to be included.

‘It is useful to know the nature of the reactions to the vaccine, not all of which were minor, but because of the size of the study it would be unwise to assume that this picture could be generalised to a larger group of similar children.’

This article originally appeared on Medscape, part of the Medscape Professional Network.