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56 HEALTH ALLERGIES FROM PAGE 55 “With any vaccination, you can expect local reactions, including injection site pain and swelling, that last from about six hours after the vaccine until the following day,” he said. “There may also be redness and swelling. “Muscle ache and headache can occur too, but generally they’re gone within a day. Also, some people get chills and fevers. “These are all normal reactions, while an allergic reaction will involve more widespread symptoms. An allergic reaction isn’t something you can self- diagnose, so, if a patient is concerned, they just need to go back to their vaccination provider and have it all checked out. “Having said that, those administering the vaccination should understand that it \[the Covid-19 vaccine\] is generally well tolerated. If there are symptoms of a local reaction or a systemic reaction, those will tend to start about six hours after the vaccine is administered, so the patient is long gone by the time any unexpected reaction is apparent.” While allergic reactions can range from mild additional discomfort to increasingly more significant symptoms, an anaphylactic reaction is far more serious and will occur much sooner. “Typically, anaphylactic reactions will occur within half an hour, almost certainly,” Professor Booy said. “They occur in about one in 100,000 people who have the Pfizer vaccine, so it’s really very rare. The risk of a blood clotting disorder is one in 200,000, so again, this is really very rare. “If an anaphylactic reaction does occur, vaccinating pharmacists, nurses and GPs are all trained to use adrenaline. That’s why, when there’s a history of allergy, patients are asked to stay behind for half an hour instead of the usual 15 minutes.” Myth busting moments Many patients were initially wary of Covid-19 vaccinations because, before the Covid pandemic, mRNA-based vaccines had not been widely used in humans. While the technology is advanced and offers a number of advantages, initial concerns were raised due to potential, unknown side effects. It didn’t help that, in Norway, early reports of deaths among the elderly after the Pfizer/BioNTech mRNA vaccine was administered were quickly followed by unproven reports of anaphylactic reactions happening at rates significantly higher than those typically expected with vaccines. This understandably led people to feel reluctance when considering their own vaccination. However, following new research into acute allergic reactions in patients receiving the Pfizer/BioNTech and Moderna Covid vaccines, it has been shown these types of allergic reactions occur in only 0.025 per cent of patients, or 2.47 per 10,000 people. The study was conducted using data drawn from vaccinations of more than 50,000 workers at a major US hospital. According to the study’s lead author, Dr Kimberly Blumenthal, Co-Director of the Clinical Epidemiology Program at Massachusetts General Hospital, when the hospital’s employee vaccination program began, the study team gathered and documented data on all allergic reactions, including anaphylaxis. “It was critical to have accurate information on allergic reactions to these new vaccines, not only for our current situation, but also because this new vaccine technology is important for future pandemic responses.” “The Covid-19 mRNA vaccines are the first vaccines of their kind, and they have remarkable efficacy and safety across all populations,” she said. “It was critical to have accurate information on allergic reactions to these new vaccines, not only for our current situation, but also because this new vaccine technology is important for future pandemic responses.” The team analysed employee questionnaires to understand the incidence of allergic reactions and applied various observation methods to identify the true incidence of anaphylaxis. Of the 52,805 employees surveyed immediately after receiving the first dose of the vaccine, including an estimated 4000 with diagnosed allergies to some foods and medications, two per cent did experience allergic reactions, while anaphylactic reactions occurred in 2.47 per 10,000 individuals. “To put this in perspective, this is largely comparable to anaphylactic reactions from common antibiotics,” Dr Blumenthal said. The investigators noted that while the rate of anaphylaxis was higher than the US Centres for Disease Control and Prevention estimate of between 0.025 and 0.11 incidences per 10,000 vaccinations, the overall risk of anaphylactic reaction to the Covid vaccine “is extremely low and comparable to other common healthcare exposures”. “An additional encouraging aspect of the study revealed that all the anaphylaxis cases fully recovered,” Dr Blumenthal said. “No patient had anaphylactic shock or required oxygen, even temporarily.” TGA injects an alternative While the risk of anaphylactic reaction to the Covid vaccine is low, it nevertheless exists, and pharmacists must always be prepared to deal with any such emergency. To support this, three new adrenaline autoinjectors for acute allergic anaphylaxis have recently been approved by the TGA, with Australian company Allergy Concepts announcing the inclusion of three adrenaline (epinephrine) autoinjectors on the ARTG for the emergency treatment of anaphylaxis due to insect stings, vaccination, food or other allergens. TGA approval of the Anapen 500, Anapen 300 and Anapen 150 Junior autoinjectors gives Australians weighing 60kg and over living with anaphylaxis access to a 500mcg adrenaline autoinjector dose for the first time. Welcoming the TGA approval and recognising that these three new autoinjectors offer prescribers and their patients a choice, Ms Said commented: “It’s important for an individual at risk of anaphylaxis, and their treating doctor, to discuss adrenaline injector device options, and to choose a device that best suits their needs. “Having the Anapen 500mcg dose available to those weighing 60kg and over in Australia is an important step forward. “The listing of Anapen also provides welcome relief to those at risk of anaphylaxis, who have long been reliant on one device, and severely impacted during manufacturing delays, product recalls, or supply shortages. “Previously, Australians needed to use expired devices for life-threatening emergencies if they occurred during TO PAGE 58 RETAIL PHARMACY • JUN 2021