Perspective

Monitoring vaccine adverse reaction reports

Continuing in our discussion on COVID vaccination and our children, the World Health Organization (WHO) defines an adverse drug reaction as “any response to a drug which is noxious and unintended, and which occurs at doses normally used in man for prophylaxis, diagnosis, or therapy of disease, or for the modification of physiological function.”

The US Food and Drug Administration (FDA) categorizes an adverse event as “any undesirable experience associated with the use of a medical product in a patient.”

The US Centers for Disease Control and Prevention (CDC) Vaccine Adverse Events Reporting System (VAERS), Europe’s EudraVigilance system and the UK’s Yellow Card Reporting System, are among the world’s major tracking systems for suspected adverse events associated with medicines and medical devices.

All platforms point out that a reported adverse event does not necessarily mean the event was caused by the medicine or substance used, but the systems are key mechanisms that enable regulators and officials to track trends, and be quickly alerted to potential problems.

EudraVigilance advises, “Before a medicine is marketed, information on its safety and efficacy is based on use of the medicine in clinical trials. However, clinical trials may not be able to detect all side effects, as they involve limited numbers of patients.

“Also, some side effects may take a long time to develop, and only occur after the clinical trial is finished. Often (but not always), people taking part in clinical trials are healthy or do not have other diseases or do not normally take other medicines. This is not the situation when the medicine is used in real life.

“Continuous monitoring after the clinical trial is therefore essential, to maintain a comprehensive safety and effectiveness profile of the medicine.”

As of May 29, 198,678 cases of adverse reactions to the Pfizer vaccine were reported to EudraVigilance, the majority of which were reported by healthcare professionals.

The adverse reactions run the gamut of categories including disorders of the cardiac, vascular, respiratory, thoracic, reproductive, immune and nervous systems, as well as disorders of the blood and lymphatic systems.

Reactions categorized as serious include 7,129 cardiac disorders, 7,808 vascular disorders, 32,644 nervous system disorders, and 4,612 blood and lymphatic disorders.

For those aged 12 to 17, there were 28 serious cardiac disorders reported, and 18 serious vascular disorders.

For all age groups, 280 cases of myocarditis were reported – eight of which were fatal – and 16 of which occurred in males ages 12 to 17.

For all groups, 233 cases of pericarditis were reported, with five occurring in those ages 12 to 17 – four males and one female.

As of May 21, 103,813 adverse reaction reports for the Pfizer vaccine in the US were reported to VAERS – 10,198 of which are listed as serious, including 1,826 deaths.

For those ages 17 and under, 3,142 adverse reactions to the Pfizer vaccine have been reported, 115 categorized as serious.

Over four million children ages 17 and under have received the Pfizer vaccine in the US thus far, according to the CDC.

There were 96 cases of myocarditis reported in those age six to 29, and 29 of those were in children age six to 17.

As of May 20, the UK’s Yellow Card Reporting System received 61,553 adverse reaction reports for the Pfizer vaccine, 382 with a fatal outcome.

There were 21 cases of myocarditis and 21 of pericarditis reported, the latter with one fatal outcome.

There were 221 strokes (cerebrovascular accident) reported – 12 of which were fatal – and 27 cases of ischemic stroke (strokes typically caused by blood clots in the brain) – one of which was fatal.

As for the AstraZeneca vaccine, 249,236 people reported adverse events to EudraVigilance for all age groups, and the UK Yellow Card system received 176,750 adverse events, 806 with a fatal outcome.

Across platforms, there have also been several reports by COVID-vaccinated mothers of adverse reactions in their breastfed babies.

Pfizer advises that, “Available data on Pfizer-BioNTech COVID-19 vaccine administered to pregnant women are insufficient to inform vaccine-associated risks in pregnancy”, and “Data are not available to assess the effects of Pfizer-BioNTech COVID-19 vaccine on the breastfed infant or on milk production/excretion.”

ADVERSE REACTIONS HERE AT HOME

The WHO defines pharmacovigilance as the science and activities relating to the detection, assessment, understanding and prevention of adverse effects or any other drug-related problem.

Reporting adverse events to a vaccine as part of an established system is new for Bahamians, but is necessary to enable the country to quickly detect problems in those who are vaccinated.

Culturally, Bahamians are hesitant about revealing or admitting to illness or the severity thereof, particularly if they fear the information might be made public, or garner unwanted scrutiny.

Given the push by government to increase COVID vaccination numbers, and a prevailing atmosphere of condemning both concerns about marketed vaccines and discussions about potential adverse events, both vaccine hesitancy and hesitancy on the part of healthcare workers and vaccine recipients in reporting adverse events, should be evaluated by officials.

The country’s system for reporting adverse events must be efficient and responsive.

AstraZeneca vaccine recipients are given a Public Hospitals Authority (PHA) flyer advising them to seek prompt medical assistance and mention recent vaccination if they experience symptoms including breathlessness, chest or stomach pain, swelling or coldness in an arm or leg, blurred vision or bleeding under the skin.

Given the wide range of suspected multisystem adverse events being reported worldwide, government should advise on whether a broadening of the reporting protocol ought to occur, to widen the scope of monitoring adverse effects not listed in the PHA flyer.

This can aid both healthcare workers and vaccine recipients in heightening awareness of potential unexpected adverse reactions, and formulating appropriate responses thereto.

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