Investigations into a possible link between the AstraZeneca Covid-19 vaccine and “extremely rare” blood clots is still ongoing, but health officials maintain the benefits still outweigh the risks.
The Medicines and Healthcare products Regulatory Agency (MHRA) is reviewing reports of a very rare and unlikely to occur specific type of blood clot in the brain, known as cerebral venous sinus thrombosis (CVST) occurring together with low levels of platelets (thrombocytopenia), following vaccination.
The investigation comes after the MHRA received 79 UK reports of blood clotting cases up 31 March.
As a result, regulators are now recommending that people aged between 18 and 29 should be offered alternatives to the AstraZeneca vaccine.
Scientists from the University of Oxford have said the risk of CVST is around eight to 10 times higher after catching the Covid-19 than getting vaccinated with Pfizer, Moderna, AstraZeneca Covid-19 jabs.
The MHRA has not yet concluded that the “extremely rare” blood clots in the brain are caused by the vaccine, and pointed to a one in a million chance of dying from a rare blood clot.
What are the side effects of the AstraZeneca jab?
The following symptoms are the most common after receiving the coronavirus vaccine, and affect more than one in 10 people. These may include:
- tenderness, pain, warmth, itching or bruising where the injection is given
- generally feeling unwell
- feeling tired (fatigue)
- chills or feeling feverish
- feeling sick (nausea)
- joint pain or muscle ache
Other common symptoms, which can affect up to one in 10 people, include:
- swelling, redness or a lump at the injection site
- being sick (vomiting) or diarrhoea
- flu-like symptoms, such as high temperature, sore throat, runny nose, cough and chills
In some cases, people may experience side effects such as swollen glands or dizziness, but these symptoms are much less common and may only affect up to one in 100 people. These include:
- feeling dizzy
- decreased appetite
- abdominal pain
- enlarged lymph nodes
- excessive sweating, itchy skin or rash
While investigations continue, the MHRA is advising as a precautionary measure that anyone who experiences symptoms four days or more after vaccination should seek medical advice. These may include:
- a new onset of severe or persistent headache, blurred vision, confusion or seizures
- develop shortness of breath, chest pain, leg swelling or persistent abdominal pain,
- unusual skin bruising or pinpoint round spots beyond the injection site
If you experience any side effects, you should talk to your doctor, pharmacist or nurse. If you are concerned about a side-effect it can be reported directly via the Coronavirus Yellow Card reporting site or search for MHRA Yellow Card in the Google Play or Apple App Store and include the vaccine brand and batch/Lot number if available.
How do everyday medicines compare?
Many of the common side effects of the AstraZeneca vaccine are similar to those listed on everyday medicines, including paracetamol and ibuprofen.
Paracetamol very rarely causes side effects, but in rare cases it is possible to have a serious allergic reaction which may cause symptoms such as:
- Skin rashes or other signs of allergic reaction, such as itching, swelling of the lips and tongue, or difficulty breathing
- Unexpected bruising or bleeding
- Persistent tiredness
- Mouth ulcers
- Sudden weight loss or loss of appetite
- Yellowing of the eyes and skin
Similarly, ibuprofen can also cause side effects with more than one in 100 people experiencing symptoms, such as headaches, dizziness, nausea, vomiting and indigestion after taking the tablets.
However, in rare cases, side effects can be more severe and may include:
- Allergic reactions, including asthma, unexplained breathing, shortness of breath, rapid heart rate, low blood pressure, collapse
- Skin problems, including hives, rash, itching, swelling of lymph nodes
- Stomach and bowel problems, including indigestion or heartburn, passing of blood, vomiting, diarrhoea, constipation
- Blood disorders, including unexplained bruising or bleeding, sore throat, mouth ulcers, fever, extreme paleness, weakness or exhaustion
- Heart and circulation problems, including increased risk of heart attack, high blood pressure or heart failure
- Liver problems, which could be indicated by yellowing or he skin and eyes, or pale coloured stools and dark urine
- Kidney problems, which may be indicated by passing more urine than normal, or pain in the back
- Nervous system problems, including headache and aseptic meningitis
Blood clots ‘extremely rare’
Both paracetamol and ibuprofen share some similar side effects to the AstraZeneca vaccine, including headache, fever, tiredness and nausea, although, much like the jab, severe reactions are very rare.
While the possible link between the vaccine and blood clots has raised concerns, figures from MHRA suggest the risk of developing a rare blood clot is the equivalent to four in every 1,000,0000 who receive the jab.
However, if you choose not to get the vaccine and you later catch Covid-19, you are two per cent more likely to develop a blood clot, with around 3,000 people per month in the UK suffering from them.
To put the figures in perspective, around two in every 1,000 women are likely to develop a blood clot during or after pregnancy, while women who take the contraceptive pill have a one in 2,000 chance of getting a blood clot.
These reports have deterred many young women from taking the pill, even though the risk of taking it is about the same as being struck by lightning - which has little more than a one in 10,000 chance.
Getting the flu jab poses a one in one million risk of developing Guillain-Barré syndrome, a rare disease that can leave you paralysed. However, this is about the same level of risk as dying in an accident while on a 10 mile bicycle ride.