Adverse reactions are typically identified through various methods including clinical trials, post-marketing surveillance, and spontaneous reporting systems. Clinical trials are essential for identifying common and serious adverse reactions before a product is approved. Post-marketing surveillance helps in detecting rare or long-term adverse effects that may not have been evident during clinical trials. Spontaneous reporting systems, like the Vaccine Adverse Event Reporting System (VAERS) in the United States, allow healthcare providers and patients to report any suspected adverse reactions.
