The study was a population-based cohort study that looked at over two million people over the age of 50 residing in Catalonia, Spain. They looked at both vaccinated and unvaccinated adults, noting those who were hospitalized for pneumonia and those who died from any cause.
The results of their study concluded that not only did the PCV13 vaccine not reduce the risk of pneumonia, it actually increased the risk among those vaccinated.
In this study, the large differences in outcomes between PCV13 vaccinated and unvaccinated suggest that vaccinated persons were sicker.
The study also found that the mortality rate was 60% higher in the vaccinated population (5,944 per 100,000) than in the unvaccinated population (2,354 per 100,000).