Pfizer & Astrazeneca COVID Vaccine Side Effects

The rollout of the coronavirus vaccine is already having a remarkable impact around the world: the latest figures show that over 34 million people in the UK have received at least one dose, making it the biggest inoculation programme the country has ever launched. 

As of April 27, a quarter of all UK adults are now fully vaccinated against coronavirus. Currently, there are three jabs on offer, chiefly AstraZeneca and Pfizer, and the roll-out of the Moderna vaccine began on Apr 7.

The Moderna coronavirus vaccine is the third jab to be rolled out in the UK, and was first administered to people in Wales, with people in England starting to receive the jab from Apr 13.

As with other vaccinations, there are several side-effects that are expected with the Covid jab. These are almost always minor, and no different to the symptoms that occur after other vaccines: muscle soreness, a slight fever and fatigue. However, in March the Government urged people who have had any side-effects from a Covid vaccine to come forward as a precaution – despite medical regulators confirming their safety.

But what are the side-effects, and why are they worse for some than others? Here is what we know…

What are the side-effects of the AstraZeneca vaccine?

The AstraZeneca vaccine lists the following side-effects that can occur after the jab: tenderness, pain, warmth, itching or bruising where the injection is given, generally feeling unwell, feeling tired, chills or feeling feverish, headache, feeling sick (nausea), joint pain or muscle ache. Ian Douglas, professor of pharmacoepidemiology at London School of Hygiene and Tropical Medicine, explains that these side-effects are “pretty common” and occur in more than one in 10 people who are given the vaccine. 

At an MHRA briefing on Apr 7, UK and EU medicines regulators concluded that blood clots should be listed as a “very rare” side-effect of the AstraZeneca vaccine.

Further to the review, the UK’s Medicines and Healthcare Regulatory Agency stated that there is a four in one million chance of getting a blood clot from the AstraZeneca vaccine. Despite the negligible risk, those aged under 30 in the UK will be offered Pfizer or Moderna instead.

In response to these concerns, an Oxford University study examined the incidence of blood clotting on the brain in coronavirus patients and AstraZeneca recipients, finding that the occurrence of brain clots from coronavirus was eight times greater the risk presented by the AstraZeneca jab. But the findings are yet to be peer-reviewed.

What are the side-effects of the Pfizer vaccine?

They’re very similar to those that sometimes occur after the AstraZeneca jab. The Pfizer vaccine lists the following side effects as very common: pain at injection site, tiredness, headache, muscle pain, chills, joint pain and fever. In almost all cases they resolve themselves in a couple of days. 

Does the AstraZeneca vaccine cause worse side-effects than Pfizer?

In recent weeks, a debate has emerged over whether the Oxford produced vaccine causes more severe side-effects. Early data collected by King’s College London suggests that around one in 10 people who had the Pfizer jab reported “systemic” after-effects, similar to mild flu symptoms; this rose to three in 10 who had the AstraZeneca.

However, at this stage we don’t know for certain if one jab produces worse side-effects than the other. Data regarding this topic, and many others, is still being collected by the Covid Symptom Study app, known informally as Zoe, which was launched by Tim Spector, professor of genetic epidemiology at King’s College London, to support important research into the virus.

Sir John Bell, Oxford University’s Professor of Medicine, has stated that he expects all vaccines to have “some background level of clotting issues”. Bell went on to say that the data on this issue was still being collected for further study.

How long do Covid vaccine side-effects last?

Not long. Dr Bharat Pankhania, an infectious disease specialist from the University of Exeter Medical School, explains that in nearly all cases “side-effects are mild, and resolve themselves very quickly.” In practice, this means that any side-effects you have will go away within a few days. 

However, one side-effect does tend to last longer than the rest: swollen glands. This usually occurs in the armpit or neck, on the same side as the arm where you had your jab and can last for up to 10 days.

If you do find yourself in discomfort, the NHS website states that you can take painkillers, such as paracetamol, as long as you stick to the usual prescribed dosage. 

Why do side-effects occur? 

The first thing to remember is that mild side-effects are common, and expected – so if you do have an achy arm after your jab, there is no reason to be alarmed. “Side-effects are a feature of all effective medications and vaccines, as they have a biological effect on the body – for example, by causing an immune response in the case of a vaccine,” says Douglas. He explains that when we receive a vaccine, our body recognises it as “foreign” and mounts an immune response. “This is the starting point of the intended effect of the vaccine. We want our body to do this so that later on, our immune system will remember and recognise the infectious agent (in this case the coronavirus), which we want to be protected against,” he says.

This response causes “inflammatory activity”, which Douglas explains leads to “inflammation, swelling and pain” in the area where we had the jab. “Biological markers of inflammation can themselves trigger further responses such as fever or headache,” he adds. 

Who gets side-effects? 

At this stage we can’t predict who will get side-effects, and why certain people get them worse than others, says Douglas. However, they are common: research by King’s College London in February found that 37 per cent of people who had the Pfizer vaccine experienced some local after-effects, such as pain or swelling near the site of the injection, after their first dose, rising to about 45 per cent of the 10,000 who had received two doses. The study also showed that 14 per cent had at least one whole-body after effect – such as fever, aches or chills – within seven days of the first dose. This rose to around 22 per cent after the second dose.

Should I be worried if I don’t have side-effects from the vaccine?

No side-effects isn’t a cause for concern. “We have no reason to think people should worry about whether the vaccine has worked for them or not, depending on whether they noticed any side effects,” says Douglas.

How common are serious side-effects?

Serious side-effects of the coronavirus vaccine are rare, and research into the links between the AstraZeneca jab and blood clots is still ongoing. Earlier this week, the Medicines and Healthcare products Regulatory Agency (MHRA) said more work was needed to establish a definite link between the AstraZeneca jab and rare brain blood clots, and that the benefit still outweighed the risk for the majority. 

However, the JCVI has recommended that under-30s be offered an alternative vaccine, such as the Moderna or the Pfizer jab. 

Concern was first raised about the link between the AstraZeneca vaccine and blood clots back in March, leading the European Medicines Agency to investigate the possible link. Of the 20 million people who had received the AstraZeneca vaccine, they only found 25 instances of these specific blood clots – seven cases of clots in multiple vessels throughout the body, and 18 cases of clots forming in brains.

After looking at all the evidence, the European Medicines Agency, the World Health Organisation and health authorities concluded that the benefits of the AstraZeneca vaccine far outweigh any risks.

This news article was originally published at Telegraph UK