The health system has mechanisms that go far beyond hospital care. Essential activities to ensure that vaccines reach the population safely are being implemented in a consistent and comprehensive manner. Among them is the almost invisible but essential work of pharmacovigilance.
The process evaluates and detects potential adverse effects related to the use of medicines and vaccines. The World Health Organization (WHO) considers post-marketing surveillance of these agents essential, because even after rigorous clinical studies on humans, which have ensured the safety and effectiveness of the product and the consequent registration of the product for use in the country, some rare or unexpected effects become noticeable only when a drug or vaccine is widely used.
It is estimated that between 5% and 10% of hospital admissions worldwide are associated with adverse drug reactions, reinforcing the importance of an effective monitoring system.
Pharmacovigilance helps enhance the safety of vaccines provided in the public health network and in private clinics. In the vast majority of cases, serious adverse events reported by residents do not have a cause-and-effect relationship with the application of immunizing agents.
In Brazil, Anvisa is responsible for the national pharmacovigilance system, which integrates public and private hospitals, health professionals, the pharmaceutical industry and patients. The system allows recording and analyzing notifications about adverse effects, therapeutic failures or quality problems reported by users.
Brazil is one of the most active countries in Latin America in this field, but challenges remain, especially in promoting a culture of reporting among professionals.
During the COVID-19 pandemic, pharmacovigilance has emerged. The rapid creation and distribution of vaccines has required extensive monitoring, and global data has proven their safety. According to the World Health Organization, more than 13 billion doses of coronavirus vaccines will have been administered by 2024, with a practically negligible rate of serious adverse events — about 0.002%.
Moreover, pharmacovigilance work plays a crucial role in combating misinformation. For example, the persistent belief that vaccines can cause autism was the result of a fraudulent study published in 1998 and has been widely debunked ever since. Robust research involving millions of children has consistently proven that there is no link between vaccines and autism.
Pharmacovigilance also contributes to improving product quality and guiding public health measures. Analysis of the data collected can lead to updating leaflets, adjusting doses and, in very rare cases, suspending medications that pose risks. It is an ongoing process that transforms the experience of patients and professionals into scientific information. This cycle of observing and learning is what ensures the development of the healthcare system.
For this process to be effective, it is necessary for everyone to participate, including inspectors, doctors, pharmacists and drug users themselves. Reporting negative feedback, even if mild, is a way to contribute to improving the system.
In a scenario characterized by rapid scientific progress and widespread circulation of information, some of which is false and disseminated on social networks, pharmacovigilance is a collective commitment to health. With everyone’s participation, it is possible to advance the production of new treatments in a responsible and transparent way, increasingly reducing risks and protecting our populations.