Covid: Decision to restrict AstraZeneca jab to over-40s is not because risk of vaccine has gone up

Tom Clarke

Former Science Editor

ITV News Science Editor Tom Clarke explains why the announcement is more about the 'decrease in Covid overall rather than the risk of the vaccine'

Today’s decision to restrict use of the AstraZeneca vaccine to the over-40s isn’t because the risk of the vaccine in that age group has gone up - it’s because the risk of them getting Covid-19 has gone way down.

According to senior government scientists, this has been one of the hardest decisions they’ve had to make regarding the vaccine roll-out so far because it’s such a finely balanced problem.On the one hand is the evidence of the risks of the vaccine: As more doses have been administered it's become clearer that the risk of the vaccine becomes greater the younger you are.

The latest data shows a risk of a blood clot after the first dose of the vaccine in people age 40 to 49 is about 1 in 95,000. For people age 30 to 39 it’s about 1 in 60,000.

Also, because the risk of a far more dangerous rare brain blood clot goes up in younger patients, the risk of dying is higher for younger people.

About four times higher in the 30 to 39 age group compared to the 40 to 49 age group.

Although, bear in mind, the overall risk of a fatal outcome overall is still very low whatever the age group.

AstraZeneca is to be restricted to the over-40s. Credit: PA

On the other hand, is the harm that can be done by taking the AstraZeneca vaccine off the schedule for 30 to 39-year-olds.

The risk of the vaccine is a one-off thing. You either get a blood clot or you don’t.

But the benefit of the vaccine is long term - lasting months or possibly a year or more.

And the benefit isn’t just for the person being vaccinated, it's for all the people they protect by having immunity to Covid.

And that extends beyond Covid, too.

The "invisible harm" caused by Covid in terms of an overstretched NHS, cancelled appointments and delays to normal care have to be factored in as well.The only reason the vaccine authority, the Joint Committee on Vaccination and Immunisation (JCVI), came to the decision they did today is because they think they can take this step without increasing the risk to 30 to 39 year-olds in the not too distant future, while preventing a wider increase in the epidemic.The rates of Covid-19 are currently so low and are likely to stay that way for some time and the risk of the vaccine for 30 to 39-year-olds is higher than the risk of Covid.

And the JCVI have been able to take the step because they’ve calculated there will be sufficient alternative vaccine available to ensure they are vaccinated before Covid rates start to rise again.

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