Saturday, August 22, 2009

Live Attenuated Flu Virus Vaccine For H1N1

A live attenuated flu vaccine is part of the vaccination procedures for the preemptive preparations to thwart the expected resurgence of the novel H1N1 Swine flu. Most people don't know that an attenuated flu vaccine is an actual live flu virus. The difference with the virus is that it has been "weakened" through a process called "passing". Passing is the process of repeatedly growing the virus over and over again in a cell culture in a lab which typically results in the virus being weakened so that it has less disease causing capacity. So part of the treatment and preliminary vaccination for the novel H1N1 Swine flu is to administer the actual Swine flu virus into individuals. Interestingly, the actual molecular basis for this attenuation or weakening is unknown and the WHO - World Health Organization states that any new attenuated virus used as a vaccine is likely to contain one or more specific mutations injected into the genome.

Attenuated viruses have been used in the past for various forms of vaccination and are also part of the regular flu vaccinations. Most often they are used as a backup when the availability of inactivated vaccines is scarce. In most instances in the past, the attenuated viruses such as Laiv(FluMist®) have helped prevent illness in individuals. Symptoms that occur after treatment with attenuated viruses can mimic illness such as runny nose, congestion, tiredness, fatigue, headache, cough. These mild effects are generally short lived compared to flu infection. However,since these treatments are the actual live flu virus there are also instances in which the recipients themselves get sick and also transmit the virus to others. The transmission rate is estimated to be 1-2.4%. The initial five target groups for preemptive vaccination against the novel H1N1 Swine flu comprises 159 million people alone in the United States. A 2% infection rate on half of this group is over 1.5 million people. Now figure in how many people who come into contact with those inadvertently infected people. So in essence the prevention procedures for the novel H1N1 Swine Flu virus could actually contribute to the development and spread of the flu virus nationally and internationally. It is a bit of a conundrum but that is the circumstance of the situation we are now facing. ( I need to point out that the flu vaccines being used will not all be attenuated virus vaccines and that many will be inactivated ( dead ) viruses)

The H1N1 Swine flu virus is a novel virus and may not respond or act typical to other flu viruses should it mutate further. It has already proved to be evolving. Reported earlier this week, it has been found that the Swine flu has now passed from humans to poultry. This should be taken seriously since the primary concern with the Swine flu is that if it should mix further with the Avian flu then the potential new strain of virus would make the current Swine flu, which is highly contagious but not deadly, a highly contagious and deadly strain that would not only affect billions of humans but meat and poultry worldwide. Stay tuned as I will continue to follow this virus and try to bring you a bit of perspective. Thanks for reading.

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World Health Organization WHO #2
Dr. Spock
Center For Disease Control
Swine Flu Confirmed In Turkeys
Universal Flu Vaccine Is Close To Development


Brian said...

I posted about swine flu on my travel blog explaining the implications on travel insurance. Good post.

A Good Time is Blog Time

TC said...

Thanks Brian. I will try to keep you updated on the latest details I can find. The implications on travel insurance are sure to be significant.