Who can't have the Pfizer/BioNTech COVID-19 vaccine?
The Pfizer/BioNTech COVID-19 vaccine has an excellent safety profile and there are only a handful of people in Aotearoa who cannot receive it. The list of reasons why the Pfizer/BioNTech COVID-19 vaccine may not be suitable is short:
Before the first dose:
History of severe allergic reaction (anaphylaxis) to an ingredient of the vaccine. This is very rare, and only applies to previous anaphylaxis to a stabiliser in the vaccine called polyethylene glycol (PEG). However, this is often unclear as problems with PEG most commonly occur after having it by mouth and there may not be any problem with having it in a vaccine. Cases like this require expert assessment by an immunology specialist.
After problems with the first dose:
People who had a severe allergic reaction (anaphylaxis) after the first dose – this typically occurs within 15 minutes of receiving it and is the main reason for waiting after vaccination. Even when suspected anaphylaxis has occurred after the first dose, increasing experience now shows that many people can be revaccinated safely in a specialist immunology clinic setting.
Those who had myocarditis (inflammation of the heart muscle) or pericarditis (inflammation of the lining around the heart) after their first dose of this vaccine. Myocarditis or pericarditis after the vaccine is rare. Diagnosis requires special tests and often assessment by a heart specialist.
In New Zealand, adverse events following immunisation (AEFI) are reported to the Centre for Adverse Reactions Monitoring (CARM).
An Adverse event following immunisation (AEFI) is an untoward medical event which follows immunisation and does not necessarily have a causal relationship with the administration of the vaccine.
A medical assessor evaluates each report to determine whether there is a plausible association between the adverse reaction and a vaccine, and those confirmed as likely AEFI are investigated further by Medsafe. This is important as, by chance, some people will experience new illnesses or die from a pre-existing condition shortly after vaccination. As part of the review process, all adverse events that may be associated with a vaccine are reviewed by an independent safety monitoring board. Deaths are also referred to the Coroner for determination of cause of death. This can be a lengthy process so deaths can be under investigation for some time.
Additionally, to determine if there are any specific trends or patterns that might indicate a safety concern, it is important to compare natural death rates to observed death rates following vaccination. International collaboration is also important to monitor for very rare events and potential safety concerns.
Medsafe safety reports showed that, as of 28 August 2021, a total of 40 deaths had been reported following COVID-19 vaccination in New Zealand. Of these, 19 were deemed not likely related to the vaccine, five could not be assessed due to insufficient information and 15 remain under investigation, as described above. One death has been considered likely due to vaccine-induced myocarditis, a known rare side effect of the Pfizer COVID-19 vaccine, the cause of death is yet to be determined by the Coroner. As might be anticipated, most deaths (34 out of 40) have been in people aged 60-79 and over 80 years, and no deaths have been reported in people under 30. To date, Medsafe has reported the observed number of deaths reported after COVID-19 vaccination is actually less than the expected number of natural deaths.
In the US, healthcare providers are required to report any death after COVID-19 vaccination, whether or not it is deemed likely to be related to vaccine administration. Over 380 million COVID-19 vaccines were administered from December 14 2020 and September 13 2021 and there were 7,653 deaths reported (0.002% of those vaccinated). A review of available clinical information has not established any causal link between Pfizer COVID-19 vaccination and death.
Myocarditis and the COVID-19 vaccine in New Zealand
An increased risk of heart inflammation (myocarditis, pericarditis, or both) has been observed in people who have received mRNA COVID-19 vaccines in overseas studies, particularly in males under 30 years of age after the second vaccine dose.
IMAC emphasises that the overwhelming benefits of vaccination in protecting against COVID-19 greatly outweigh the rare risk of these conditions, and Comirnaty (Pfizer mRNA vaccine) continues to be recommended for all people ≥ 12 years of age who do not have any contraindications to the vaccine.
For 1-3 days after vaccination, some people can feel unwell with headaches, tiredness muscles aches, chills or a mild fever, this a normal response, and is more common after the second dose and in younger people. If unwell, you are advised to rest, drink plenty of fluids and to avoid vigorous exercise, until you are feeling better. If symptoms persist after a few days or worsen, to seek medical advice.
For further information for health practitioners, see ‘ In-depth information’ below.
Following a press release issued by the Ministry of Health on 30 August regarding the death of a woman in the days following vaccination with the Pfizer COVID-19 vaccine, the Ministry of Health states the case has been referred to the Coroner and the cause of death has not yet been determined. The CV-ISMB considered that the myocarditis was probably due to vaccination but noted that there were other medical issues occurring at the same time which may have influenced the outcome following vaccination.
What is myocarditis and can it occur after Pfizer (Comirnaty) vaccination? An increased risk of heart inflammation (myocarditis, pericarditis, or both) has been observed in people who have received mRNA COVID-19 vaccines in overseas studies, particularly in males under 30 years of age after the second vaccine dose.
Myocarditis symptoms include chest pain, feelings of having a fast-beating, fluttering or pounding heart and shortness of breath. One or more of these symptoms can occur shortly after vaccination due to stress or anxiety. However, if anyone experiences these symptoms after receiving Comirnaty (Pfizer mRNA vaccine) from more than 6 hours to 7 days (typically around 1 to 5 days), they should seek immediate medical attention.
The benefits of vaccination in protecting against COVID-19 greatly outweigh the risks of adverse events including myocarditis. The risk of myocarditis from COVID-19 infection is almost four times higher than from vaccination. Confirmed cases are rare.
Cases after vaccination are more frequently reported following the second dose and in males 12 to 30 years. Even in this group, risk is less than 1 in 25,000 vaccine recipients.
How severe is myocarditis? Most reported cases of myocarditis and pericarditis, linked to mRNA vaccination, have required hospital care for assessment and monitoring, because sudden death is a rare complication of myocarditis (read more: what happens if a death occurs following immunisation). More than 8 out of 10 of the reported cases have recovered quickly with rest and commonly used oral anti-inflammatory medications such as ibuprofen. Longer-term follow-up of these cases is ongoing.
Advice about being vaccinated
Comirnaty (Pfizer mRNA vaccine) continues to be recommended for all people from 12 years of age. The only contraindication to the vaccine is anaphylaxis to a vaccine component which is very rare and requires specialist review.
If feeling unwell after vaccination, it is advised to rest, drink plenty of fluids and avoid vigorous activities, such as going to the gym. Seek medical advice if symptoms worsen, or persist for longer than 3 days.
All episodes of myocarditis and pericarditis following Comirnaty should be reported to CARM.
For further advice and for plans for the patient’s next vaccination, please call 0800 IMMUNE (0800 466 863) or email [email protected]
Information in-depth for health professionals:
A risk of myocarditis and pericarditis has been observed in people who have received mRNA COVID-19 vaccines overseas, particularly in males under 30 years of age after the second vaccine dose.
IMAC emphasises that the overwhelming benefits of vaccination in protecting against COVID-19 greatly outweigh the rare risk of these conditions, and Comirnaty (Pfizer mRNA vaccine) continues to be recommended for all people ≥ 12 years of age who do not have any contraindications to the vaccine. Recent data from Israel showed three excess cases of myocarditis per 100,000 doses following Comirnaty vaccination versus 11 excess per 100,000 cases with COVID-19 infection.
Most myocarditis and pericarditis cases linked to mRNA vaccination receive hospital care for assessment and monitoring. Most reported cases have been mild and patients have recovered quickly with standard treatment. Longer-term follow-up of these cases is ongoing. However, sudden death may be a rare complication of myocarditis so careful assessment and management of suspected cases is important.
Symptoms usually appear from 1 to 5 (median 2) days of vaccination and include acute chest pain or pressure, pain with breathing, palpitations, increased sweating, fainting or shortness of breath with exercise, at rest or when lying down. People who experience any of these symptoms after having Comirnaty should seek prompt medical attention.
Symptoms such as palpitations, chest pain or feeling short of breath can occur in the first hours after vaccination in some people – symptoms appearing in this time frame are consistent with an immunisation stress reaction. This is too soon after vaccine receipt for heart inflammation due to vaccination to appear.
Initial investigations for people presenting with symptoms or signs which may be consistent with myocarditis or pericarditis should include ECG, troponin, +/- CRP, chest X-ray, and investigations for other differential diagnoses as clinically indicated.
Findings consistent with myocarditis include elevated troponin and ECG changes including paroxysmal or sustained atrial or ventricular arrythmias, AV node conduction delays, intraventricular conduction defects or frequent atrial or ventricular ectopy.
Those suggestive of pericarditis include a pericardial rub, and with a large pericardial effusion pulsus paradoxus and distant heart sounds may be evident on clinical examination.
ECG changes can include widespread ST segment elevation or PR depression.
If initial screening investigations are abnormal, patients should urgently be referred to hospital for further investigations and cardiac monitoring. Patients with more severe clinical presentations may require referral prior to full investigations.
If clinical suspicion of myocarditis or pericarditis is high, further advice should be sought, even if screening investigations are thought to be normal.
Precautions to vaccination with cardiac conditions
Most pre-existing cardiac conditions are not regarded as contraindications to Comirnaty vaccine. However, young people who have active or clinically unstable heart disease, should be advised to seek medical care promptly if they develop new or worsening pre-existing symptoms. A precautionary review in the days after their vaccination may also be advised. Those with a history of pericarditis or myocarditis, unrelated to Comirnaty, may have the vaccination if the condition is completely resolved, (i.e. no symptoms and no evidence of ongoing heart inflammation).
People who develop myocarditis or pericarditis attributed to their first dose of Comirnaty are advised to defer further doses. They should be referred to IMAC for clinical advice about alternate vaccine options. Vaccination is not advised for anyone with current active cardiac inflammation. High intensity exercise should be avoided until complete resolution of inflammation and normalisation of cardiac function.
All episodes of myocarditis and pericarditis following Comirnaty should be notified to CARM.
Gargano JW, Wallace M, Hadler SC, et al. Use of mRNA COVID-19 Vaccine After Reports of Myocarditis Among Vaccine Recipients: Update from the Advisory Committee on Immunization Practices - United States, June 2021. MMWR Morb Mortal Wkly Rep. 2021;70(27):977-82. doi: 10.15585/mmwr.mm7027e2
What is known about the AstraZeneca COVID-19 vaccine (in use overseas) and blood clots?
A very rare clotting disorder has been reported overseas following vaccination with viral vector COVID-19 vaccines in younger adults.
A very rare and new type of adverse event has been observed following vaccination with the AstraZeneca, and more recently the Janssen, viral vector COVID-19 vaccines overseas (including Australia). Although, the reason why this may occur is unknown, it has been proposed the vaccine can induce an immune response where the body incorrectly attacks its own cells to make platelets very sticky. This results in the formation of blood clots in unusual places such as the brain or abdomen. This is similar to a recognised side effect of heparin, a commonly used medication used in hospital.
The unusual characteristic of this type of clotting disorder (thrombosis) is that it is also associated with bleeding due to a lack of platelets in the blood (thrombocytopenia) - the sticky platelets clump together to form clots and this attracts more platelets from the blood - named thrombosis with thrombocytopenia syndrome (TTS). The only risk factor that has been identified so far is age - most cases have occurred in adults aged under 50 years. See the Brighton collaboration for the interim case definition. Also please find a video by The Melbourne Vaccine Education Centre explaining TTS in more detail.
This is a very rare event (around 7-10 cases per million doses in those aged under 50 years) and the risk from COVID-19 is significantly higher than the risk of TTS. For this reason, regulatory authorities overseas are weighing up the benefit and potential risk of this vaccine and some have advised age related precautions.
What side effects may be expected after vaccination?
The most common responses to the COVID-19 vaccine are injection-site reactions (sore arm for example) and general symptoms such as ‘flu-like’ illness, headache, chills, tiredness, nausea, fever, dizziness, weakness or aching muscles.
Generally, these potential responses happen within a day or two after the vaccination and are not associated with more serious or lasting illness. These types of reactions reflect the normal immune response to this vaccine. Not everyone experiences this type of response. They are more likely after the second dose and tend to resolve within a day or two. Pain relief, such as paracetamol or ibuprofen, is not recommended to be taken before having the vaccine but can be used after it if required.
In addition, as with any vaccine or medicine, there is a risk of allergic reactions shortly after the vaccinations. Because of this people should wait at a vaccination centre as instructed after having their vaccine. Those with previous allergic reactions or anaphylaxis should tell their vaccinator before going ahead.