In 2008 some scientists held on really tightly to a theory- inflammation in the lungs lead to hypertension in the arteries, and that extra pressure would lead to inflammation in the arteries and increase the risk of pieces breaking off. Those pieces would be responsible for heart attacks and strokes, and therefore vaccinating to prevent lung-related diseases would reduce the risk of heart attack and stroke. There was even a study of World War II veterans that purported a link between vaccines and lower cardiovascular event rates.
But that's why researchers test and re-test new findings. A study of over 84,000 men in the Kaiser Permanente Northern and Southern California health plans looked for a relationship between heart attack, stroke, and pneumococcal vaccination status. They examined the records of men with no prior history of cardiovascular problems. The authors found no protective measure of vaccination against the heart attack or stroke rate, regardless of risk or age group. The researchers re-worked the numbers against a more strict disease coding system and reported repeatable results.
Hung Fu Tseng, PhD; Jeffrey M. Slezak, MS; Virginia P. Quinn, PhD; Lina S. Sy, MPH; Stephen K. Van Den Eeden, PhD; Steven J. Jacobsen, MD, PhD (2010). "Pneumococcal Vaccination and Risk of Acute Myocardial Infarction and Stroke in Men." JAMA 2010;303(17):1699-1706.