People are two-and-a-half times more likely to feel “a bit rough” after the AstraZeneca vaccine than the Pfizer jab, according to Professor Luke O’Neill.
A new study in the Lancet Medical Journal followed over 627,000 people who were vaccinated between December and March.
It found that 13.5% of people experienced ‘systemic side effects’ after the first does of Pfizer and 22% experienced them after the second.
Meanwhile 33.7% of people experienced them after the first does of AstraZeneca.
On The Pat Kenny Show this morning, Professor O’Neill said systemic side effects are “flu-like symptoms and muscle aches which resolve after about a day.”
“That means you might have a fever or you might have muscle aches around your body,” he said.
“Like the symptoms of the flu basically so systemic means it is more than one part of your body is aching.
“Not many get a fever actually that is unusual but these percentages mean you do feel a little bit off; a little bit groggy really.”
The study also found that more Pfizer patients experienced ‘local side effects’ – such as arm pain following the injection.
Some 71.9% of patients given the Pfizer vaccine experienced local effects after the first jab an 68.5% experienced them after the second.
Some 58.7 experienced local effects after their first does of AstraZeneca.
The study did not report on the second dose of AstraZeneca.
Infection
Professor O’Neill said the study also found differences in people who had been infected with COVID in the past.
“A fascinating one was, if you have been infected before and you have one shot of Pfizer, you have more symptoms the next day,” he said.
“So, in other words, if you feel extra rough, say after the Pfizer first shot, it probably means you have been infected. It is almost like as if the infection is a bit like one shot of the vaccine.
“But then, as ever, the evidence is really good, it always resolves. In the vast majority of people, taking a paracetamol helps and then within about a day, most people are back to normal.”
The Lancet study found that AstraZeneca patients were 1.6 time more likely to experience side-effects if they had previously been infected.
For Pfizer patients that rose to 2.9 times more likely.
In terms of local effects, patients who has previously been infected were 1.4 times more likely to experience effects after AstraZeneca and 1.2 times more likely after Pfizer.
Protection
Professor O’Neill said the study also threw up fascinating figures on how long it takes for the vaccines to take effect.
“The first shot of any of them, within about five or six days, your immune system is kicking off,” he said. “By about day nine post-vaccination then it begins to plateau.”
“In other words, you are now fully on the go in terms of your immune system and that persists then for weeks and weeks.
“The second shot’s job is mainly to make that last even longer; to cause a more durable response and protect you for months and months and months.
“We know now the first jab is actually very protective indeed. The J&J vaccine is a one-shot anyway so they are all very similar in terms of protection after the single shot.”
EU travel pass
He noted that it is unfair not to offer people EU travel passes after one shot – because people have to wait much longer for their second shot of AstraZeneca.
“They should change that for definite, that is unfair,” he said.
“We know the first shot of AstraZeneca is very protective so why they shouldn’t be allowed to have a travel pass … They should definitely change that I think.”
The Lancet study is available here.
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