Adverse reactions remain uncommon, occurring in roughly one case per thousand vaccinations.
Em todo o mundo, a confiança nas vacinas não se constrói apenas com aprovações científicas, mas com a disposição coletiva de relatar o que acontece depois da seringa. Portugal juntou-se esta semana a 63 outros países na campanha #MedSafetyWeek, lembrando que o silêncio sobre reações adversas não protege ninguém — antes priva as autoridades da informação de que precisam para distinguir o risco real da perceção do risco. A vigilância farmacológica é, no fundo, um ato de cidadania: cada relato, por menor que pareça, contribui para o mapa que orienta decisões que afetam milhões.
- Com mais de 15.900 reações adversas suspeitas registadas em Portugal desde o início da vacinação contra a COVID-19, a dimensão dos dados exige interpretação cuidadosa — e não alarme.
- 85 mortes entre doentes idosos foram associadas a reações adversas, um número que pesa sobre o debate público e obriga as autoridades a comunicar com precisão redobrada.
- A subnotificação é o verdadeiro adversário da campanha: quando as pessoas não reportam, os reguladores ficam cegos a padrões que só emergem com milhares de relatos acumulados.
- O Infarmed apela a profissionais de saúde e cidadãos para que usem o portal RAM, reforçando que reportar uma reação não equivale a provar que a vacina a causou.
- A mensagem central da semana é de equilíbrio: as vacinas salvam vidas, as reações adversas são raras — cerca de um caso por mil vacinações —, mas o sistema de segurança só funciona se todos participarem.
Portugal participou esta semana na sexta edição da campanha internacional #MedSafetyWeek, uma iniciativa coordenada pelo Uppsala Monitoring Centre em colaboração com a Organização Mundial de Saúde que reúne agências reguladoras de 64 países. O objetivo é simples e urgente: encorajar profissionais de saúde, doentes e familiares a reportar reações adversas suspeitas a vacinas — incluindo as vacinas contra a COVID-19 — em vez de as ignorar ou guardar para si.
O Infarmed partiu de uma premissa honesta: as vacinas salvaram milhões de vidas, mas, como qualquer medicamento, podem causar efeitos indesejados. Esses efeitos só importam para a saúde pública se forem comunicados. Por isso, os profissionais que administram vacinas são incentivados a falar previamente com os doentes sobre possíveis reações, preparando-os para reconhecer sinais e compreender que reportar não é o mesmo que acusar.
Os dados portugueses oferecem uma perspetiva concreta. Entre 27 de dezembro de 2020 e finais de setembro de 2021, foram registados 15.922 relatos de reações suspeitas em cerca de 16 milhões de doses administradas. Desses, 5.929 foram classificados como graves — incluindo 557 hospitalizações, 158 situações de risco de vida e 85 mortes, todas em doentes idosos. As reações mais frequentes foram dor de cabeça, febre e dores musculares, sintomas que, em escala, formam os padrões que os reguladores precisam de monitorizar.
O Infarmed foi explícito na contextualização: as reações adversas são raras, ocorrendo em cerca de um caso por mil vacinações. A autoridade alertou também para os riscos de comparar diretamente os números entre vacinas — Pfizer, AstraZeneca, Moderna e Janssen foram usadas em populações diferentes, em momentos distintos e em circunstâncias epidemiológicas variadas, o que torna qualquer comparação direta enganosa.
A mensagem final da campanha não é que as vacinas são isentas de risco — nenhum medicamento o é. É que o sistema que permite identificar e gerir esses riscos depende inteiramente da disposição das pessoas para falar. Em Portugal, qualquer cidadão pode reportar uma reação suspeita através do portal RAM no site do Infarmed. O silêncio, concluem as autoridades, é o maior obstáculo à segurança coletiva.
Portugal's drug regulator joined a coordinated global effort this week to encourage the reporting of suspected vaccine side effects, marking the sixth consecutive year the country has participated in the international #MedSafetyWeek campaign. The initiative, running through November 7th, brings together medicine agencies from 64 countries in a social media-driven push to make clear that adverse reactions to vaccines—including COVID-19 shots—should be reported to health authorities rather than dismissed or kept private.
The National Medicine Authority, known as Infarmed, framed the campaign around a simple premise: vaccines have saved millions of lives, but like all medicines, they can cause unwanted effects, and those effects matter only if someone reports them. The goal is to empower healthcare workers, patients, caregivers, and family members to speak up when something seems wrong after vaccination. Healthcare providers administering vaccines are being asked to discuss potential side effects with patients beforehand, so people know what to watch for and understand that reporting a reaction is not the same as proving the vaccine caused it.
The numbers from Portugal tell a particular story. Between the start of the vaccination campaign on December 27, 2020, and late September 2021, the country recorded 15,922 reports of suspected adverse reactions across nearly 16 million doses administered. Of those reports, 5,929—or 37 percent—were classified as severe. The breakdown of severity is granular: 3,612 reactions were deemed clinically important, 1,517 caused temporary disability (including missed work), 557 required hospitalization, 158 posed a life-threatening risk, and 85 resulted in death, all among elderly patients. The remaining 63 percent of reports were classified as non-severe.
Infarmed was careful to contextualize these figures. Adverse reactions remain uncommon, occurring in roughly one case per thousand vaccinations. Of the severe cases, about 85 percent involved temporary incapacity or other clinically significant effects as assessed by the person reporting—whether a healthcare professional or a patient themselves. The most frequently reported reactions were headache (3,826 cases), fever (3,820), muscle pain (3,744), pain at the injection site (3,347), fatigue (1,864), chills (1,618), nausea (1,453), joint pain (1,187), and general malaise. These are the signals that matter to regulators: patterns that emerge only when thousands of people report their experiences.
The data also showed variation across vaccine types. Pfizer/BioNTech accounted for 8,434 reported reactions out of 10.7 million doses given. AstraZeneca had 4,293 reports from 2.2 million doses. Moderna reported 1,778 reactions from 1.9 million doses, and Janssen 1,340 from 1.1 million doses. Infarmed explicitly cautioned against drawing safety conclusions from these numbers, noting that the vaccines were used in different population groups, at different times, and under different epidemiological circumstances—meaning the raw counts do not permit direct comparison of safety profiles.
The campaign itself is being run by the Uppsala Monitoring Centre, which collaborates with the World Health Organization on international drug safety surveillance. In Portugal, anyone can report a suspected adverse reaction through the RAM portal on Infarmed's website. The message being sent this week is not that vaccines are risk-free—no medicine is—but that the system for understanding and managing those risks depends entirely on people being willing to report what they experience. Silence leaves regulators blind. Reporting, even of minor or uncertain reactions, builds the picture that allows authorities to spot genuine problems and reassure the public about genuine safety.
Notable Quotes
Vaccines are the best way to protect citizens against infectious diseases and have already saved millions of lives, but like all medicines, they can cause adverse reactions that must be reported.— Infarmed (National Medicine Authority)
Adverse reactions are uncommon, with approximately one case per thousand vaccinations.— Infarmed
The Hearth Conversation Another angle on the story
Why does a country need to run a campaign asking people to report side effects? Shouldn't that happen automatically?
You'd think so, but it doesn't. Most people who have a headache or fever after vaccination assume it's normal and move on. They don't think to report it. Healthcare workers are busy. Patients don't always know where to report, or they worry they'll be blamed for complaining. The system only works if people actively choose to tell someone.
So the 15,900 reports from Portugal—is that a lot or a little?
It's actually quite small relative to the doses given. Nearly 16 million vaccinations, 15,900 reports. That's less than one-tenth of one percent. Most of those are mild things like headache or fever. The severe ones—the 5,929—that's about 0.04 percent. The deaths, 85 out of 16 million doses, are even rarer. But rare doesn't mean unimportant. If a pattern emerges, regulators need to see it.
The source says authorities can't compare safety between vaccines because they were used in different groups. What does that mean?
Pfizer was given to healthcare workers first, younger people. AstraZeneca went to older populations. Moderna came later. So if one vaccine shows more reports of blood clots, you can't say it's actually less safe—maybe older people just report more, or they're more prone to clots anyway. You're comparing apples to oranges unless you control for who got what and when.
Why emphasize that reactions are rare—one per thousand—if you're trying to get people to report them?
Because it's true, and because trust matters. If authorities downplay risks, people stop listening. If they exaggerate, people panic. The honest message is: reactions happen, they're uncommon, and we need to know about them so we can spot real problems. That's more credible than either extreme.
What happens after someone reports a reaction?
It goes into a database. Regulators look for patterns—if suddenly fifty people report the same rare symptom, that's a signal. They investigate. They might change how the vaccine is given, who it's given to, or what warnings doctors provide. Or they might conclude it's coincidence and the vaccine is fine. But without reports, they're flying blind.