Protection provided by vaccine
The COVID-19 virus causes an acute respiratory infection, where the clinical picture can vary from asymptomatic to very severe, even requiring intensive care. Additionally some patients may suffer from long-term consequences, like fatigue, bronchoconstriction, cough as well as pain in the joints or thorax. COVID-19 vaccines prevent the severe form of the illness effectively and decrease the risk of hospitalization and long-term consequences. The vaccines also somewhat prevent infections.
COVID-19 infections occur despite vaccines, but vaccinated people get probably milder infections than those without vaccination. The vaccine gives a clearly better and more long-lasting protection against severe disease than against the infection itself.
The COVID-19 virus is constantly transforming, and therefore the efficacy of the vaccines against the new virus variants and infections is monitored continuously. The COVID-19 vaccines provide fairly good protection against the new COVID-19 variants so far recognised, but the protective efficacy may by weaker against certain variants. Lately COVID-19 vaccines have been developed that are tailored against a particular variant of the virus. However, more research is needed and is being conducted constantly.
Further reading