Covid booster: Four side effects seen in ‘more than half’ of those who mix-and-match jabs

Covid booster: Four side effects seen in ‘more than half’ of those who mix-and-match jabs

The Covid booster campaign was launched in a bid to tackle waning immunity and novel variants, and so far it has proven a tremendous success. Data suggests those who have completed a full course of COVID-19 vaccines have significantly helped curb hospitalisation rates across the country. But much of the attention has now shifted towards ensuring uptake of the follow-up doses, particularly in younger age groups. A new study conducted by the National Institutes of Health has offered insight into which side effects can be expected from mixing and matching vaccines.

New findings published in The New England Journal of Medicine, have confirmed that adults who previously received a full course of vaccines with either Moderna, Pfizer, or Johnson & Johnson, could safely receive an additional booster dose from any of these manufacturers.

The new report details findings from 458 adults who were inoculated with any of the three EUA COVID-19 vaccines at least 12 weeks prior to the study enrolment.

At enrolment, each participant was administered a single booster jab.

A total of 150 subjects received a Johnson & Johnson vaccine, while another 154 received a Moderna booster and a further 154 received a Pfizer vaccine.

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The report states: “Depending on which primary vaccine regimen a participant had received, the booster vaccines were either different than (mixed, or heterologous) or the same (matched, or homologous) as the original vaccine.”

The authors continued: “The trial participants kept diaries of any side effects.

“More than half of participants reported headache, pain at the injection site, muscle aches and malaise. No serious vaccine-related adverse events were reported.”

What’s more, all combinations of primary and booster vaccines resulted in increased neutralising antibody levels.


The booster vaccines work by reminding the immune system how it responded to prior infection or teaching it how to react to an evolved threat.

It does so by prompting the body to produce neutralising antibodies that intercept the virus before it infects our cells.

The top-up proved necessary after data from Israel showed a significant drop-off in protection against infection from Covid after three months.

It revealed people were 15 times more likely to be infected, six months after receiving a second dose of the vaccine.

More than 889,700 teenagers have had their first dose of the vaccine since the programme was rolled out to the age group in August.

The NHS adds: “More than 600,000 in this age group have had their second jab.”

Previously, the booster vaccine was only recommended by the Joint Committee on Vaccination and Immunisation for clinically vulnerable 16 and 17-year-olds at higher risk for COVID-19.

The campaign was extended to all 16 and 17-year-olds after it emerged a booster significantly increases protection against the novel Omicron variant.

Published at Fri, 28 Jan 2022 08:21:00 +0000