Currently there is no scientific research if the vaccine is directly affecting menstruation. Although, there are reported changes in periods following vaccination, which shouldn’t be of concern and are temporary only. But if you find irregularities beyond one cycle, of experience extreme pain and/or loss of lot of blood, it is recommended to get an opinion from your doctor about your symptoms. In any event, it is too early to associate it with the vaccine and its effects appear to be temporary and harmless.