BCG vaccine fine powder. Sometimes the powder is sealed with vacuum in a glass ampoule. Such a glass ampoule has to be opened slowly to prevent the airflow from blowing out the powder. Then the powder has to be diluted with saline water before injecting. The history of BCG is tied to that of smallpox. Jean Antoine Villemin first recognized bovine tuberculosis in 1854 and transmitted it, and Robert Koch first distinguished "Mycobacterium bovis" from "Mycobacterium tuberculosis". Following the success of vaccination in preventing smallpox, established during the 18th century, scientists thought to find a corollary in tuberculosis by drawing a parallel
Inoculation theory (1995) posited that the use of inoculation strategies for these types of campaigns should be utilized to enhance the corporations' credibility and aide in maintaining the existing consumer attitude. This strategy should not be used to change consumer attitudes. Based on the analysis of previous research Burgoon et al. concluded issue/advocacy advertising is most effective for reinforcing support and avoid potential slippage in the attitudes of supporters. Based on previous publications they looked to test three hypotheses. The first was that issue/advocacy advertisements work to inoculate against counterattitudinal attacks. Next, issue/advocacy advertisements work to protect the source credibility. Lastly, conservatives