HuffPost UK reader Ed asked: “What should I do if I experience a negative side effect of the Covid-19 vaccine?”
For some, side effects are part and parcel of having the Covid-19 vaccine – but they’re not thought to be particularly serious.
The most common side effects of the vaccines are a sore arm (as the vaccine is administered into the upper arm), headache, feeling tired or achey, and feeling nauseous or being sick.
It’s understood that we get these reactions because our immune response is being triggered by the body to the vaccines.
What are the possible side effects?
Side effects appear to be less common in those aged over 55 than those aged 16 to 55. While they can crop up after the first dose, that shouldn’t put you off having the second dose as side effects are reported to be milder the second time around.
With the Pfizer vaccine, any side effects you do experience should be mild or moderate and go away within a few days. In a final safety analysis of the vaccine involving more than 21,000 participants, the most common side effects were injection site pain, fatigue, and headache.
Other side effects which are quite common, impacting around one in 10 people, include: muscle pain; chills; joint pain; fever; and nausea.
There have been cases where people have had more uncommon side effects, thought to affect up to one in 100 people, such as enlarged lymph nodes and generally feeling unwell. Rare side effects, which impact one in 1,000 people, include temporary one-sided facial drooping and in very rare instances, severe allergic reactions.
Those with a history of anaphylaxis to food, an identified drug or vaccine, or an insect sting can still receive the Covid-19 vaccine, as long as they are not known to be allergic to the vaccine ingredients, the Medicines and Healthcare products Regulatory Agency (MHRA) has said.
The Pfizer vaccine, for example, contains polyethylene glycol (PEG) – a known allergen commonly found in medicines, household products and cosmetics.
If you are allergic to PEG, you can have the AstraZeneca vaccine instead. If you don’t know whether you’re allergic to PEG, it’s worth bearing in mind that people with undiagnosed PEG allergy may have a history of unexplained anaphylaxis or anaphylaxis to multiple classes of drugs. Chat to your GP if you’re worried.
The British Society for Allergy and Clinical Immunology (BSACI) has said people who have a localised itchy skin reaction to the first dose of a Covid-19 vaccine should receive the second dose with prolonged observation afterwards (roughly 30 minutes) in a setting with full resuscitation facilities.
Severe allergic reactions are very rare and usually happen within minutes of having the vaccine. It’s important to remember that the staff giving the vaccine are also trained to deal with allergic reactions – so you’re in safe hands.
The AstraZeneca vaccine has similar common side effects to the Pfizer jab. These include: tenderness pain, warmth, redness, itching, swelling 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.
Side effects impacting up to one in 10 people include: a lump at the injection site; fever; being sick; and flu-like symptoms (high temperature, sore throat, runny nose, cough and chills). While uncommon symptoms, affecting one in 100 people, include: dizziness; decreased appetite; abdominal pain; enlarged lymph nodes; excessive sweating; and itchy skin or a rash.
In clinical studies, most side effects from both jabs were mild to moderate in nature and resolved within a few days.
It’s thought people who’ve had Covid-19 before might be more likely to experience side effects from the vaccine. Research from New York found people with Covid-19 antibodies were more likely to report fatigue, headache, chills, fever and muscle or joint pain after receiving a single dose of an mRNA vaccine (which is what the Pfizer jab is), The Times reported.
Recently, several European countries paused vaccination with the jab over fears it could be linked to blood clots in some patients.
In the UK, the Medicines and Healthcare products Regulatory Agency (MHRA) has acknowledged there might be a link, but said more work is needed to establish “beyond all doubt that the vaccine has caused these side effects”.
The MHRA said it identified 79 cases of rare blood clot events after the first dose of the AstraZeneca vaccine out of 18.1m doses of the jab administered up to and including March 31. Of the 51 women and 28 men affected, 19 died. The risk is equivalent to four people in one million.
As a safety precaution, those aged between 18-29 may be offered an alternative vaccine instead – either the Pfizer or the Moderna jabs.
The European Medicines Agency’s safety committee has concluded that “unusual blood clots with low blood platelets should be listed as very rare side effects” of the Oxford/AstraZeneca vaccine – but that the benefits of the vaccine still significantly outweigh the risks.
You feel rough after your jab. Now what?
First of all, there’s no need to panic. Like the flu shot or any other vaccine for that matter, you might feel a bit rubbish in the next few days.
If you have mild side effects like aches, pains and fever the NHS suggests taking a painkiller such as paracetamol. It’s quite common to get a mild fever after the jab which resolves itself in roughly 48 hours – if you have a fever for longer than that, or any other symptoms of the virus, consider getting a Covid-19 test.
People who experience any side effects, whether mild or more severe, can report these on the Yellow Card website to help inform vaccine safety going forward. This includes side effects that might not be listed above.
Some side effects might impact your ability to drive and use machines – so if you do feel unwell after the jab, you’re urged not to use them until the symptoms pass. The good news is that the expected benefits of both Covid-19 vaccines in preventing the virus and any serious complications far outweigh any known side effects.
As a precaution, anyone who experiences a headache for more than four days after having the AstraZeneca jab, as well as bruising somewhere other than the injection site after a few days, should seek medical attention.
The EMA and MHRA recommend patients should seek urgent medical assistance if they have the following symptoms after the AstraZeneca vaccine: shortness of breath, chest pain, swelling in your leg, persistent abdominal pain, neurological symptoms including severe and persistent headaches or blurred vision, and tiny blood spots under the skin beyond the site of injection.
If you have other symptoms that become worse or start to cause concern, you should seek medical assistance by calling 111 or your GP practice. Or, in an emergency, phone 999.
Experts are still learning about Covid-19. The information in this story is what was known or available at the time of publication, but guidance could change as scientists discover more about the virus. To keep up to date with health advice and cases in your area, visit gov.uk/coronavirus and nhs.uk.