色情视频

At health clinics across the country, people are lining up to get vaccinated with the seasonal flu vaccine, the H1N1 vaccine or both -- so many people that there aren鈥檛 enough doses to vaccinate them all.

Health officials are rationing the supplies they do have for those who need them most, including people in high-risk groups, like small children, or those with preexisting health conditions.

Shortage of the Vaccine

鈥淭he classical approach for making influenza vaccines is you have to grow the virus,鈥� said Edward Morgan, 色情视频 research professor, about the vaccine shortage. 鈥淪ince a virus does not grow like a bacteria does, in a culture, you have to grow it in cells. Normally they grow these in duck eggs. So as a result, it takes a while to be able to generate enough material.鈥�

After the virus is grown, according to Morgan, it has to be deactivated, either with a chemical interaction or a heat treatment, so it doesn鈥檛 grow any more. Mass production of the vaccine is difficult because of the time it takes to produce the virus, coupled with the liklihood that virus will mutate.

Mutating Virus

Morgan, who works in , explained that the reason people need to get a seasonal flu shot each year is because one of the two key components of the virus mutate each year. What makes the H1N1 virus so unique is that both major components are mutating.

鈥淲here it becomes problematic is because you鈥檝e got a shift in both of these particular proteins on the surface,鈥� Morgan said. 鈥淎nd it seems to be, for whatever reason, a very potent combination that a lot of (peoples鈥� immune systems) haven鈥檛 seen.鈥�

Morgan explained that, because the H1N1 strain is similar to the epidemic from 1918, older people may have already been exposed to it at some point, and therefore are not as susceptible as the younger generation.

For more information about the H1N1 virus and vaccinations at San Diego State, visit the university's