Saturday, October 30, 2010
Influenza - A Great Presentation from the CDC
August 30th Presentation by the CDC
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There's a great powerpoint presentation from the CDC dated August 30, 2010. It includes a discussion of the disease, the varying death rates (in years when H3N2 predominates there are 2.7 times more deaths than when H1N1 or Influenza B dominates). There's a discussion of the recent Hutterite colony study showing that vaccinating children protects others. There's even an explanation of blood levels of antibodies. You really don't need a medical or scientific background to understand the presentation.
A lot of great information.
Friday, October 29, 2010
Hepatitis B at Birth or For The Very Young
The US is unusual in vaccinating all newborns against Hepatitis B at birth. Much more common is only vaccinating high risk babies at birth. The definition varies by country but it always includes mothers known to be Hepatitis B positive.
Because Hepatitis B is often transmitted sexually, there's a concern that vaccinating against Hepatitis B somehow sexualizes the innocent newborn as Hep B is usually transmitted through sexual contact.. But here's the punch line most don't know: While vaccinating all newborns is unusual, vaccinating very young infants against Hepatitis B is not.
Parents who are concerned about Hepatitis B vaccination of newborns and the very young should have their concerns allayed when they realize that: "As of 2007, 171 of the 193 member countries of the World Health Organization (WHO) had implemented the recommendations of the Expanded Programme on Immunization to offer universal hepatitis B vaccination to infants"
I live in the province of Ontario, Canada, which only vaccinates high risk infants at birth and vaccinates the rest of the population in Grade 7 through a school vaccination program. That's quite unusual. A recent article in the Canadian Medical Association Journal Hepatitis B immunization strategies: timing is everything explains the benefits of universal vaccination of infants. I strongly recommend that concerned parents read this article..
For the American view on vaccination at birth see A Comprehensive Immunization Strategy to Eliminate Transmission of Hepatitis B Virus Infection in the United States Recommendations of the Advisory Committee on Immunization Practices (ACIP) Part 1: Immunization of Infants, Children, and Adolescents December 23, 2005
My personal view: There's no downside to the American practice except cost and causing unfounded fears in some parents. In a country where health care isn't supplied universally, a system that provides a safety net by vaccinating at birth seems to make sense.
In any case add Hep B to the DTaP or DTaP-IPV vaccine series that starts at 2 months so that an additional injection isn't needed.
The evidence doesn't support waiting until adolescence to protect against Hepatitis B.
Here's a great quote from the CMA Journal article
Because Hepatitis B is often transmitted sexually, there's a concern that vaccinating against Hepatitis B somehow sexualizes the innocent newborn as Hep B is usually transmitted through sexual contact.. But here's the punch line most don't know: While vaccinating all newborns is unusual, vaccinating very young infants against Hepatitis B is not.
Parents who are concerned about Hepatitis B vaccination of newborns and the very young should have their concerns allayed when they realize that: "As of 2007, 171 of the 193 member countries of the World Health Organization (WHO) had implemented the recommendations of the Expanded Programme on Immunization to offer universal hepatitis B vaccination to infants"
I live in the province of Ontario, Canada, which only vaccinates high risk infants at birth and vaccinates the rest of the population in Grade 7 through a school vaccination program. That's quite unusual. A recent article in the Canadian Medical Association Journal Hepatitis B immunization strategies: timing is everything explains the benefits of universal vaccination of infants. I strongly recommend that concerned parents read this article..
For the American view on vaccination at birth see A Comprehensive Immunization Strategy to Eliminate Transmission of Hepatitis B Virus Infection in the United States Recommendations of the Advisory Committee on Immunization Practices (ACIP) Part 1: Immunization of Infants, Children, and Adolescents December 23, 2005
My personal view: There's no downside to the American practice except cost and causing unfounded fears in some parents. In a country where health care isn't supplied universally, a system that provides a safety net by vaccinating at birth seems to make sense.
In any case add Hep B to the DTaP or DTaP-IPV vaccine series that starts at 2 months so that an additional injection isn't needed.
The evidence doesn't support waiting until adolescence to protect against Hepatitis B.
Here's a great quote from the CMA Journal article
Chronic HBV infection, with the attendant risk of cirrhosis and hepatocellular carcinoma, occurs in 1%–5% of adults and up to 90% of infants who are infected with HBV. Providing vaccinations during adolescence without offering vaccinations during infancy misses this critical period when the acquisition of a HBV infection can be the most harmful. Epidemiologic studies show that the age distribution of HBV varies by jurisdiction and suggest that roughly one-third of chronic infections are acquired during infancy and early childhood. An idealvaccine schedule should protect against infection both in infancy, when the risk of becoming a chronic HBV carrier is highest, and in adolescence, when high-risk sexual and drug-using behaviours occur more frequently.
Epidemiologic data are critical for informing decisions about vaccination. Estimating the age-specific incidence of acute infections is valuable for planning prevention measures. However, acute infections in infants and toddlers may be missed because HBV infection is often asymptomatic in young children. In many jurisdictions, the age-specific incidence of HBV infection is unknown.
Thimerosal and Light Tuna
A full dose of flu vaccine that uses thimerosal as a preservative contains 25 millionths of a gram of ethylmercury or 25mcg or 25ug. That's the amount you find in flu vaccine that comes in ten dose vials. Vaxigrip (approved for use in Canada) has much less thimerosal in each dose from a 10 dose vial because they've shortened the time from first dose to last dose allowed from the usual 30 days down to 7 days. See my blog entry.
20mcg is the usual amount of methylmercury found in a can of 'light' tuna. There are difference between methylmercury and ethylmercury, but the similarity in the amounts of a can of light tuna fish, which Canada, doesn't restrict in the diets of pregnant women and a once a year flu shot, helps put the amount of thimerosal in flu vaccine in perspective.
And for those who believe that injection versus eating matters, here's a surprise. If you were to accidentally or deliberately swallow the mercury from an old thermometer, without inhaling it, you would be OK. Because almost all the mercury goes straight through your body. But almost all the methylmercury from food you eat does reach the bloodstream. Eventually it will be excreted, but that's also true of the ethylmercury in thimerosal.
Scripter, who comments at Huffington-Post has put together a nice list of resources on the can of tuna versus flu vaccine issue. Here it is.
20mcg is the usual amount of methylmercury found in a can of 'light' tuna. There are difference between methylmercury and ethylmercury, but the similarity in the amounts of a can of light tuna fish, which Canada, doesn't restrict in the diets of pregnant women and a once a year flu shot, helps put the amount of thimerosal in flu vaccine in perspective.
And for those who believe that injection versus eating matters, here's a surprise. If you were to accidentally or deliberately swallow the mercury from an old thermometer, without inhaling it, you would be OK. Because almost all the mercury goes straight through your body. But almost all the methylmercury from food you eat does reach the bloodstream. Eventually it will be excreted, but that's also true of the ethylmercury in thimerosal.
Scripter, who comments at Huffington-Post has put together a nice list of resources on the can of tuna versus flu vaccine issue. Here it is.
As if it would do any good. Once someone latches onto a conspiracy theory, there's no letting go. Unfortunately, this is a dangerous one, since some people will be scared into not getting immunized for a variety of diseases, which could lead to their reintroduction to the general population (see, whooping cough) So, OK, I'll bite:
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Wednesday, October 20, 2010
Analysis of Oral Argument of Vaccine Case Before the Supreme Court.
An appellate lawyer did a 5 minute video discussing the oral argument of the vaccine case before the US Supreme Court. He wrote the brief for the US Chamber of Commerce supporting the vaccine maker.
He explains the issue very well.
He's got a great analysis of the oral argument. How do I know it is great? It matches the views I had before watching the video. In particular, he (and I) would stress the importance of the argument on the timing of the switch from OPV to IPV. He ends the video by saying that he was fairly confident that the decision would be the one he wants. I also scanned his brief. This is one impressive lawyer. Here is his CV.
Consider spending 5 minutes listening to what he has to say.
Monday, October 18, 2010
Source Drying, Not Herd Immunity, But Wow
Many vaccination opponents scoff at the idea of herd immunity. This is a great document by the World Health Organization that explains many of the concepts important in vaccination, including herd immunity.
When there is herd immunity, there won't be an outbreak of a disease. Here, I'm not referring to herd immunity, but to source drying. Source drying occurs when vaccinating a target population benefits another population. It is explained in the WHO document.
Go look at pages 8 and 13 of the CDC's June 2010 slide presentation to the US vaccine recommendation body, ACIP, on the effectiveness of Rotavirus vaccines. 2008 was a year in which zero two years old had been vaccinated against Rotavirus, but younger children had been. Even though the percentage of younger kids vaccinated wasn't that impressive, there was a huge decrease in the number of serious Rotavirus infections in the 2 year olds --- none of whom had been vaccinated against the disease. Wowser.
Another example of source drying is the recent study that concluded: "Immunizing children and adolescents with inactivated influenza vaccine significantly protected unimmunized residents of rural communities against influenza." The study is "Effect of Influenza Vaccination of Children on Infection Rates in Hutterite Communities A Randomized Trial" Targeted vaccination of children can make a difference to others.
Vaccinating your child can protect others even without herd immunity because of source drying. And if other people have vaccinated their children, it makes it less likely your child will be sick if they aren't vaccinated or if the vaccine doesn't result in a strong immune response.
When there is herd immunity, there won't be an outbreak of a disease. Here, I'm not referring to herd immunity, but to source drying. Source drying occurs when vaccinating a target population benefits another population. It is explained in the WHO document.
Go look at pages 8 and 13 of the CDC's June 2010 slide presentation to the US vaccine recommendation body, ACIP, on the effectiveness of Rotavirus vaccines. 2008 was a year in which zero two years old had been vaccinated against Rotavirus, but younger children had been. Even though the percentage of younger kids vaccinated wasn't that impressive, there was a huge decrease in the number of serious Rotavirus infections in the 2 year olds --- none of whom had been vaccinated against the disease. Wowser.
Another example of source drying is the recent study that concluded: "Immunizing children and adolescents with inactivated influenza vaccine significantly protected unimmunized residents of rural communities against influenza." The study is "Effect of Influenza Vaccination of Children on Infection Rates in Hutterite Communities A Randomized Trial" Targeted vaccination of children can make a difference to others.
Vaccinating your child can protect others even without herd immunity because of source drying. And if other people have vaccinated their children, it makes it less likely your child will be sick if they aren't vaccinated or if the vaccine doesn't result in a strong immune response.
Wednesday, October 6, 2010
Urabe MMR in the UK 1988-1992
Dyson wrote a nice comment at Huffington-Post on the history of the use in the UK of MMR vaccines that contained the Urabe strain of mumps vaccine from 1988-1992.
The US, Canada and UK use only the Jeryl Lynn strain of mumps vaccine in Merck's MMRII vaccine. It does not cause aseptic meningitis. Urabe strain based mumps vaccine causes aseptic meningitis. That's not a nice adverse event. However, aseptic meningitis caused by vaccine strain mumps virus does not cause permanent damage. Considering that aseptic meningitis from wild mumps strains only very rarely causes permanent damage that isn't so surprising. Vaccines that include Urabe strain mumps virus are still used today.
Here's the comment.
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