What do we know about vaccine safety?
“COVID-19 has been a global health event of unprecedented impact with recorded cases now estimated to exceed 700 million and deaths exceeding 7 million. While the public health emergency of international concern was declared over on the 5th of May 2023, the impact of COVID-19 continues. The ability to rapidly develop a number of vaccines that were approved by regulatory bodies and deployed around the world has undoubtedly had a tremendous impact, with estimates suggesting cases averted as a result of vaccination likely to be at least in the 10s of millions and deaths in the 100s of thousands, if not millions.
Vaccines for COVID-19 were able to be developed rapidly due to many important innovations and based on many years of research, preparing to be able to more rapidly respond to a novel emerging pathogen such as that responsible for COVID-19.
All the usual phases of clinical trials (including with placebo controls) were completed with numbers of participants exceeding that usually seen in other similar clinical trials. To achieve regulatory approval, these vaccines (as with all vaccines that are approved by our and other similarly rigorous regulators) demonstrated both high levels of efficacy as well as safety. Once approved, safety as well as effectiveness was continued to be carefully observed, and while it is clear that vaccines for COVID-19 are associated with adverse events (as with essentially any intervention), for the majority of vaccines approved, the rate of related adverse events was such that the benefits outweighed these risks hence these regulatory approvals and associated recommendations have remained in place. The raw number of adverse events may seem high, especially if compared to other vaccines, however, the denominator, or number of doses given in such a short space of time, which is now over 13.5 billion doses of COVID-19 vaccines, does need to be taken into account.
The distinction between correlation and causation also needs to be considered given the majority of the world’s population has now been vaccinated. This does not mean that anything bad that happens to anyone is a direct result of having received a COVID-19 vaccine.”
On the US Vaccine Adverse Event Reporting System – what it is, its limitations and how it compares to Australia’s vaccine event reporting systems.
“Adverse event reporting systems are an important part of the ongoing monitoring of the safety of vaccines, both in the USA as well as here in Australia. We do however, need to make sure that this data is interpreted correctly. The reporting of adverse events or deaths that occur after someone has been vaccinated does not necessarily mean the vaccine directly or even indirectly caused the event or death. Once again, the distinction between correlation and causation is important. The VAERS website provides guidance on interpretation to this effect, even stating, ‘VAERS collects data on any adverse event following vaccination, be it coincidental or truly caused by a vaccine. The report of an adverse event to VAERS is not documentation that a vaccine caused the event’, however, this point is often omitted when this data is used to try to overestimate safety concerns of vaccines (VAERS – Guide to Interpreting VAERS Data).”
On other safety concerns
“When assessing vaccines in clinical trials, for regulatory approval and for ongoing use, safety remains the primary consideration and is very carefully monitored. If it is not abundantly clear that the benefits of a vaccine outweigh the risks that are associated (and there are always some risks), it will not progress through clinical trials, much less be approved and used. Unfortunately, misinformation such as the firmly refuted link between vaccination and autism can cause tremendous harm and undermine trust in vaccination, such that the impact of vaccine preventable diseases is greater than it should be.”