What do we know about the AstraZeneca vaccine and blood clots?
Dr Khan examines what we know about the suspected link between the vaccine and blood clots and relates his experience of vaccinating people in his community on a vaccination bus.
The team at Oxford-AstraZeneca must be tearing their hair out after yet another week of hitting the headlines over a possible link between the vaccine and rare blood clots.
Back in March, the European Medicines Agency (EMA) said it had found no link between the vaccine and an “overall risk” of blood clots. The agency could not completely rule it out, however, and asked governments to “raise awareness” about blood clots and include information about them for healthcare workers and people who were being vaccinated. Later, the agency said these rare blood clots should be listed as potential “rare side effects” of the vaccine.
Since then, the UK’s Medicines and Healthcare Products Regulatory Agency (MHRA) has taken precautionary steps and advised anyone with potential symptoms of a blood clot four days or more after getting the vaccine to seek urgent medical advice while it investigated claims of a link with the vaccine further. On April 7, it stated that: “It is preferable for people under the age of 30 with no underlying health conditions to be offered an alternative vaccine where possible once they are eligible.” This is because while the benefits of having the vaccine vastly outweigh the risks for those in higher age groups, the balancing act becomes trickier for those statistically less at risk of being hospitalised by COVID-19. The agency was careful to point out that there is still no conclusive evidence that the vaccine causes clots, but that the links were getting “firmer”.
The statement went on to add: “Public Health England (PHE) analysis indicates that the COVID-19 vaccination programme prevented 6,100 deaths in those aged 70 and older in England up to the end of February. All safety reports are rigorously investigated and anyone with unexpected symptoms should speak with a healthcare professional. All medicines have a risk of side effects.”
The MHRA says symptoms of a blood clot would depend on the site of the blood clot:
A clot in the lungs: shortness of breath, chest pain.
A clot in the abdomen: abdominal pain and/or swelling.
A clot in the blood vessels in the brain: headache (starting four days after the vaccine), blurred vision, confusion or seizures.
A clot in the leg: swelling and/or redness in the leg.
The agency also advises anyone with an unexplained pin-prick rash or bruising beyond the injection site to speak to a healthcare professional.
While this may worry some people, it is important to state that the Oxford-AstraZeneca vaccine is safe and effective for the vast majority of people and the risk of getting clots from a coronavirus infection is far higher than the risk of getting them from the vaccine.
The MHRA, the World Health Organization and the European Medicines Agency have concluded that the balance is very much in favour of
Progress Report: Pfizer vaccines may soon be available for children aged 12 to 15
On Friday, April 9, Pfizer BioNtech applied to the Food and Drug Administration in the US for approval for the emergency use of its COVID-19 vaccine for adolescents aged 12 to 15.
Pfizer said it plans to request similar rulings by other regulatory authorities worldwide in the coming days. The statement comes on the back of phase-three trials the company has been carrying out on 12 to 15-year-olds which they say has shown 100 percent efficacy and a robust antibody response. It added that, while all participants will continue to be monitored for long-term side effects, overall the vaccine was well tolerated and side effects reported were on a similar scale to those aged 16 to 25.
The Pfizer vaccine uses mRNA technology to initiate an immune response that has been shown to protect those vaccinated from symptoms of COVID-19. After being injected, the mRNA instructs human cells to start making proteins similar to the spike protein found on the outer surface of the coronavirus. These proteins are recognised as “foreign” by the host’s immune system, which then mounts an attack destroying the spike proteins and any cells that may be containing them.
Longer-lasting immune cells then patrol the body. Should the vaccinated person contract the real coronavirus, these patrol cells will immediately recognise the spike protein on the surface of the virus as “foreign” and mount a much quicker immune attack on the virus and any cells it has managed to invade before the person becomes sick with the disease.
There are many experts who say that to get this pandemic under control we must aim for a “zero-COVID strategy”, and vaccinating children in an effort to stop its spread is part of that.
However, this is not as simple as vaccinating children against diseases like measles or polio, which we know can make them extremely sick. When assessing the use of the vaccine in young people, the risk of side effects is extremely important. Healthy young people are very unlikely to become sick from COVID-19 – many will display no symptoms at all. However, they may play a part in passing the virus on to other people, and it is here where the difficult decision to vaccinate a cohort of the population to protect others has to be taken.
Of course, there is a concern that the virus could make young people with underlying health conditions, especially those with a disorder of the immune system, very sick and approval of the vaccine for these young people seems far more advantageous. The fact that the vaccine has been well-tolerated overall will help the FDA and other regulatory bodies make an informed decision.
And now, some good news: New Zealand a year on
Most countries look to New Zealand and its leader, Jacinda Ardern, with mixed feelings of hope and envy. The country, with a population of 4.9 million, has recorded just 26 COVID-19 deaths since the onset of the pandemic just over a year ago.
Nearly every positive case in the last six months has been found to have been imported from abroad. Whenever a positive case is found in New Zealand, the country investigates vigorously and local lockdown measures are imposed. On February 14, 2021, when three cases of community transmission were discovered in Auckland, shops were closed, non-local travel banned and socialising restricted to household bubbles.
Currently, New Zealand has no concerns about community transmission and is focusing all its efforts on border control in its continuing bid to keep COVID cases at zero. New Zealand has among the strictest border control measures in the world, with anyone entering the country having to quarantine for 14 days in a hotel.
This is in sharp contrast to countries like the UK, which has seen devastating numbers of deaths from COVID-19 and, until recently, has failed to secure its borders. Instead, the UK is now putting all its eggs in one basket: vaccination.
With most of the world unvaccinated, there remains a clear and present danger of new variants being imported from abroad or as case numbers dwindle, people unwittingly bringing back variants from foreign holidays. Unlike New Zealand, which took quick and decisive action to eliminate COVID and where now residents can enjoy a near-normal life, albeit within the confines of their own borders, many countries have been left with no choice but to reduce COVID numbers to “acceptable” levels and live with a risk of seasonal spikes in cases, hospital admissions and even deaths.
There will always be the argument that New Zealand is a small island nation and it was relatively easy for it to control its borders and eliminate the virus, but speaking as someone who lives on a small island – though with a much larger population – I can say with a degree of confidence that we can all learn lessons from Jacinda Ardern and New Zealand.
On the vaccination bus: Taking vaccines out of the clinic, into the community
Much has been said about the lower level of vaccine uptake in people from minority backgrounds in Western countries, and much has been done to improve vaccine uptake in these groups. I have spoken about the barriers that people from these communities face when accessing healthcare and in turn their trust in the vaccine. The reasons are multifaceted and complex.
One way to show that health professionals take their health seriously and want to protect them against COVID-19 is to take the vaccine out of clinics and directly into the community.
This approach has proven to be effective in the past when clinicians went to mosques, gurdwaras and temples to vaccinate people. Backed by religious leaders, confidence in the vaccine has been given a boost.
But not all people from minority backgrounds visit places of worship and there is a danger that a certain cohort of this “hard to reach” population will be missed. Now, some parts of the UK are using a “COVID vaccination bus” in areas that have seen lower uptake of the vaccine in the first phase of the vaccine rollout.
When we did this in my area in northern England, it was not just people from minority backgrounds the bus was aimed at helping, but also those from poorer areas that often have reduced uptake of the vaccine.
Our bus was armed with hundreds of doses of the Oxford-AstraZeneca vaccine, which can be transported far more easily than the Pfizer doses because of refrigeration requirements. Along with a willing group of clinicians, we drove into communities that had lower uptakes of the vaccine.
We had a fabulous response; people were curious as to why a vaccine bus had parked in their street and came out of their homes to ask questions. Anyone over the age of 50 or in a high-risk group was offered the vaccine and many people took up the offer. For those without a car or the funds for public transport, getting to a vaccine centre can be difficult, so having the bus come to them was a huge benefit. People who were vaccine-hesitant were given the opportunity to ask questions and we were able to clear up some of the vaccine myths and misinformation that have been circulating.
I had vaccinated people in mosques previously and had thoroughly enjoyed the experience; it was the same with the vaccine bus. If we want to engage with these communities and protect them from a virus that has disproportionately affected people from poorer backgrounds and those from minority groups we must meet them on their terms, and this is one way to do it.
Reader’s question: When will it be safe to stop wearing masks?
It has been a long year of restrictions and, with many countries accelerating their vaccination programmes, many people are asking when they can meet family and friends without masks.
It is a tricky one; we know the vaccines protect against symptoms of COVID and we know they are likely to help reduce transmission of the virus, but we do not have conclusive evidence of this yet. Furthermore, there are still large swathes of the population that are unvaccinated, so mask-wearing is still compulsory in many indoor areas.
A poll conducted by New Scientist of leading experts across the UK found the majority of them thought mask-wearing was likely to continue until at least 2022. And, even after countries have stopped mandating mask-wearing, it is thought many people will choose to continue to wear them in crowded spaces.
We saw this happen in the Far East after the SARS outbreak, where populations continued to wear masks – something that may have contributed to lower numbers of deaths from COVID-19 in the early stages of the pandemic when other Western countries were still grappling with the idea of wearing face masks.
I expect this will not make me popular among readers here, but I think that mask-wearing to some degree in certain situations may well be here to stay for the next year at least.