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Vaccine safety
Vaccines are administered mainly to children and healthy people to prevent the spread of serious and potentially fatal infectious diseases. They are one of the most powerful prevention tools available to public health and have a positive risk/benefit ratio.
Vaccines are pharmaceutical products subject to constant monitoring and are authorised based on the quality, safety and efficacy requirements defined by the applicable European and international guidelines and standards, based on their specific characteristics.
Online misinformation and disinformation on vaccines is a particular concern because it spreads and fuels baseless fears, despite the fact that it has been widely disproved by numerous scientific studies.
Stages of vaccine development
The development of a vaccine is a long and complex process that takes years and follows the same stages as the development of a drug.
Before a vaccine can be used in the preliminary stages, in preclinical and clinical trials in humans, its safety and tolerability and the absence of side effects have to be exhaustively studied and the vaccine proven safe.
In the case of COVID-19 vaccines, the health emergency made it possible to speed up the development and approval stages. Pharmaceutical companies made use of existing research work on human coronaviruses and messenger RNA (mRNA) technology, thanks to the large financial resources made available in a very short time. Moreover, evaluation and study phases were conducted in parallel and evaluation by the authorities took precedence over other drugs. This extraordinary effort led to the rapid approval of COVID-19 vaccines.
Vaccine approval
The scientific data presented by pharmaceutical companies on new vaccines are evaluated by the competent authorities, which issue an opinion on the benefits and risks to health associated with use of the vaccine.
A vaccine receives the go-ahead for approval only when its efficacy rates are very high and the benefit it can bring to people far outweighs the risks, so that it can be included in mass vaccination programmes.
Even after approval, a vaccine will continue to undergo careful and constant monitoring to verify compliance with the standards set by international bodies, such as the EMA (European Medicines Agency) and WHO (World Health Organisation), and all adverse events are monitored and analysed.
Only when efficacy rates are very high and the benefit to people far outweighs the risk, is the opinion positive and are vaccines approved for subsequent inclusion in mass vaccination programs.
Even after approval, the vaccine continues to be subject to rigorous and constant monitoring to verify compliance with the standards set by international organizations such as EMA (European Medicines Agency) and WHO (World Health Organization), and all adverse events are monitored and analyzed.
Adverse events
Like all medicines, vaccines, even if proven safe and effective, are not completely free from the risk of adverse events. The side effects associated with the vaccine are usually mild, such as fever or a general feeling of being unwell, caused by the body's immune response to the vaccine. In other cases, local reactions such as mild pain and redness at the injection site occur, which, however, do not require medical attention. The risk of adverse reactions is very low, lower than that of more commonly and frequently used drugs.
In Italy, a system has been put into place for reporting adverse events: the National Pharmacovigilance Network, which is part of the Italian Medicines Agency (AIFA). Italian reports are then forwarded to the European database, to collect all possible adverse events, even unpredictable ones, and warning signs or other health risks, so that they can be monitored and continuously and promptly investigated.
Eventi avversi
Come tutti i farmaci, anche se sicuri ed efficaci, i vaccini non sono totalmente esenti dal rischio di eventi avversi. Gli effetti indesiderati sono comunemente di lieve entità, ad esempio febbre o malessere, e sono dovuti alla risposta immunitaria dell’organismo al vaccino. In altri casi si verificano reazioni locali come dolore modesto e arrossamento nel punto di iniezione: non richiedono cure mediche. Il rischio di reazioni avverse è molto basso, inferiore a quello di farmaci di uso più comune e di più frequente utilizzo.
In Italia è presente un sistema di raccolta delle segnalazioni degli eventi avversi: è la Rete nazionale di farmacovigilanza che fa capo all’AIFA (Agenzia italiana del farmaco). Le segnalazioni italiane sono poi inoltrate al database europeo. In questo modo tutte le eventualità di eventi avversi, anche imprevedibili, e i segnali di allarme o i rischi per la salute sono raccolti, monitorati e investigati continuamente e tempestivamente.