I can understand why tobacco plants might be used to combat the flu, as there are studies where smokers benefited during the 1918 flu pandemic.

However, what worries me is how flu shots are currently mass-produced and makes me wonder how growth is accelerated using tobacco as currently they use viruses and tumor cells.

Investigating Viruses in Cells Used to Make Vaccines; and Evaluating the Potential Threat Posed by Transmission of Viruses to Humans

Virus-based vaccines are made in living cells (cell substrates). Some manufacturers are investigating the use of new cell lines to make vaccines. The continual growth of cell lines ensures that there is a consistent supply of the same cells that can yield high quantities of the vaccine.

In some cases the cell lines that are used might be tumorigenic, that is, they form tumors when injected into rodents. Some of these tumor-forming cell lines may contain cancer-causing viruses that are not actively reproducing. Such viruses are hard to detect using standard methods. These latent, or "quiet," viruses pose a potential threat, since they might become active under vaccine manufacturing conditions. Therefore, to ensure the safety of vaccines, our laboratory is investigating ways to activate latent viruses in cell lines and to detect the activated viruses, as well as other unknown viruses, using new technologies. We will then adapt our findings to detect viruses in the same types of cell substrates that are used to produce vaccines. We are also trying to identify specific biological processes that reflect virus activity.

[link to www.fda.gov]