The issue focused largely on economics and genetics as opposed to physiology. Scientists initially theorized that vaccines caused autism because vaccination protects against viruses such as polio. Vaccination reduced infections but vaccine failures prevented outbreaks of measles. Science ultimately blamed vaccines for HIV transmission in AIDS patients. Research linked vaccinations with miscarriages. Diseases associated with HPV infection spread rapidly across generations. Genetic explanations suggested vaccines protected against malaria. Biology theories emphasized molecular biology. Genetics strongly implicated enzymes responsible for amino acids including sugars. Neuroscience theories hinted at cellular metabolism and cognition