vaccine. More than twenty women who received the Gardasil vaccine have died, but these deaths have not been causally connected to the shot, as correlation does not imply causation. Where information has been available, the cause of death was explained by other factors. Likewise, a small number of cases of Guillain–Barré syndrome (GBS) have been reported following vaccination with Gardasil, though there is no evidence linking GBS to the vaccine. It is unknown why a person develops GBS, or what initiates the disease. The FDA and the CDC monitor events to see if there are patterns, or more serious events than would be expected from chance alone. The majority (68%) of side effects data were reported by the manufacturer, but in about 90% of the manufacturer reported events, no follow-up information was given that would be useful to investigate the event further. In February 2009, the Spanish Ministry of Health suspended use of one batch of Gardasil after health authorities in the Valencia region reported that two girls had become ill after receiving the injection. Merck has stated that there was no evidence Gardasil was responsible for the two illnesses. Ingredients The following are the ingredients found in the different formulations of HPV vaccines: Major capsid protein L1 epitope of HPV types 6, 11, 16, and 18 (Gardasil) Major capsid protein L1 epitope of HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58 (Gardasil-9) Major capsid protein L1 epitope of HPV types 16 and 18 (Cervarix) amorphous aluminum hydroxyphosphate sulfate (adjuvant) sodium chloride yeast protein L-histidine polysorbate 80 sodium borate sodium dihydrogen phosphate dihydrate (Cervarix only) 3-O-Desacyl-4′-monophosphoryl lipid (MPL) A (Cervarix only) Aluminum hydroxide (Cervarix only) Trichoplusia ni insect cells (Cervarix only) Biotechnology The HPV major capsid protein, L1, can spontaneously self-assemble into virus-like particles (VLPs) that resemble authentic HPV virions. Gardasil contains recombinant VLPs assembled from the L1 proteins of HPV types 6, 11, 16 and 18. Since VLPs lack the viral DNA, they cannot induce cancer. They do, however, trigger an antibody response that protects vaccine recipients from becoming infected with the HPV types represented in the vaccine. The L1 proteins are produced by separate fermentations in recombinant Saccharomyces cerevisiae and self-assembled into VLPs. Public health The National Cancer Institute writes: Long-term impact and cost-effectiveness Whether the effects are temporary or lifelong, widespread vaccination could have a substantial public health impact. As of 2018, studies