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#1
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Chickenpox Vaccine Found to Fade in a Year
http://www.nytimes.com/2004/02/24/he...cy/24CHIC.html
Vaccination against chickenpox has been routine in the United States for nearly a decade. But outbreaks of the illness among children who have already been immunized have raised new concerns about the effectiveness of the vaccine and the age when it is given. Now a new study is adding to the debate. Researchers at Yale Medical School reported last week in The Journal of the American Medical Association that the effectiveness of the chickenpox vaccine fades substantially a year after it is administered. The vaccine also appears to confer less immunity to children younger than 15 months. The chickenpox vaccine has been approved for use in the United States since 1995. Some experts have questioned whether it should be used at all, arguing that immunizing children just pushes the disease into adulthood, when it is usually more severe. |
#2
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Chickenpox Vaccine Found to Fade in a Year
"Roger Schlafly" wrote in message .net...
You really need to read the scientific articles, not the media snippets. http://www.nytimes.com/2004/02/24/he...cy/24CHIC.html Vaccination against chickenpox has been routine in the United States for nearly a decade. But outbreaks of the illness among children who have already been immunized have raised new concerns about the effectiveness of the vaccine and the age when it is given. You should read the article instead of the NYT media snippet, Roger. Now a new study is adding to the debate. Researchers at Yale Medical School reported last week in The Journal of the American Medical Association that the effectiveness of the chickenpox vaccine fades substantially a year after it is administered. The vaccine also appears to confer less immunity to children younger than 15 months. The term "fades substantially" is never used in the article. It is a NYT interpretation of the data. The term substantially was used to describe the difference between year 1 and the compiled incidence in years 2 through 8. The term "fades" is never used in the article. The statement for the one year effect is as follows: "its effectiveness decreases significantly after 1 year, although most cases of breakthrough disease are mild." The term "significant" is relatd to the statistical test of difference in RR between Year 1 and subsequent years. The chickenpox vaccine has been approved for use in the United States since 1995. Some experts have questioned whether it should be used at all, arguing that immunizing children just pushes the disease into adulthood, when it is usually more severe. Pushing the disease into adulthood for those who remain unvaccinated, Roger. However, in the JAMA publication, the authors make no such conjecture nor provide any data on this issue. A quote from the interview in the NYT article: "Up to 8 years, the protection is very good," Dr. Vazquez said. "But will it hold 10, 12, or 20 years down the line? We don't know yet." It is interesting to note that in Table 3, the effectiveness of the vaccine seems to stabilize at year 3 and shows no significant decline between years 3 and 8 - hovering in the 81 to 84% range. If vaccination is administered at 15 months or older, the overall 8 year composite effectiveness is 88%. At years 2 through 8, there is NO significant difference in effectiveness by age of vaccination. (Table 4). The data show that the effectiveness of a single dose strategy over time (up to 8 years post-vaccination) is about 81-88% depending on various factors and that in the vaccinated but infected cohort, the severity of the disease is generally mild, milder than in unvaccinated. "The vaccine is a success in reducing the risk of varicella in children. This study indicates that at least through the first 8 years after vaccination, the overall effectiveness of live, attenuated varicella vaccine remains good, although breakthrough varicella is not rare. Most vaccinated children who develop chickenpox have mild disease, regardless of their age at the time of vaccination or the time since vaccination, at least up to 7 to 8 years after vaccination (ie, the vaccine's effectiveness against moderate to severe disease is excellent throughout the period of the study)." The authors final statement is: "It is important to monitor closely the incidence of varicella and the effectiveness of the vaccine over time to determine if a booster dose is needed to improve its effectiveness." And for John: "Financial Disclosures: Dr LaRussa is the recipient of a contract from Merck & Co to perform a varicella-specific PCR assay on blinded samples from recipients of varicella vaccine who have had adverse events potentially related to vaccination. Dr Gershon has received research support for a basic science project from Merck & Co. Drs Shapiro and Gershon served as consultants at a 1-day meeting on vaccine cost-effectiveness sponsored by Merck & Co." js |
#3
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Chickenpox Vaccine Found to Fade in a Year
"Jonathan Smith" wrote in message
m... "Roger Schlafly" wrote in message .net... You really need to read the scientific articles, not the media snippets. http://www.nytimes.com/2004/02/24/he...cy/24CHIC.html [...] Now a new study is adding to the debate. Researchers at Yale Medical School reported last week in The Journal of the American Medical Association that the effectiveness of the chickenpox vaccine fades substantially a year after it is administered. The vaccine also appears to confer less immunity to children younger than 15 months. The term "fades substantially" is never used in the article. It is a NYT interpretation of the data. The term substantially was used to describe the difference between year 1 and the compiled incidence in years 2 through 8. The term "fades" is never used in the article. The statement for the one year effect is as follows: "its effectiveness decreases significantly after 1 year, although most cases of breakthrough disease are mild." "Fades substantially," "decreases significantly".... po-TAY-to, po-TAH-to; to-MAY-to, to-MAH-to... Anal to the core, eh, Jon? The term "significant" is relatd to the statistical test of difference in RR between Year 1 and subsequent years. The chickenpox vaccine has been approved for use in the United States since 1995. Some experts have questioned whether it should be used at all, arguing that immunizing children just pushes the disease into adulthood, when it is usually more severe. Pushing the disease into adulthood for those who remain unvaccinated, Roger. ....OR those in whom vaccine-induced immunity has significantly (oops, sorry! *substantially*) waned (faded, decreased, whatever). However, in the JAMA publication, the authors make no such conjecture nor provide any data on this issue. A quote from the interview in the NYT article: "Up to 8 years, the protection is very good," Dr. Vazquez said. "But will it hold 10, 12, or 20 years down the line? We don't know yet." Hehehe. Good luck getting adults to get boosters; look at the lines we already have to endure for tetanus shots! g It is interesting to note that in Table 3, the effectiveness of the vaccine seems to stabilize at year 3 and shows no significant decline between years 3 and 8 - hovering in the 81 to 84% range. If vaccination is administered at 15 months or older, the overall 8 year composite effectiveness is 88%. Aw, shucks! That's less than the figure--90%--that public health folks claim is necessary to acheive/sustain "herd immunity," isn't it? The sky is falling! At years 2 through 8, there is NO significant difference in effectiveness by age of vaccination. (Table 4). The data show that the effectiveness of a single dose strategy over time (up to 8 years post-vaccination) is about 81-88% depending on various factors and that in the vaccinated but infected cohort, the severity of the disease is generally mild, milder than in unvaccinated. "The vaccine is a success in reducing the risk of varicella in children. This study indicates that at least through the first 8 years after vaccination, the overall effectiveness of live, attenuated varicella vaccine remains good, although breakthrough varicella is not rare. Most vaccinated children who develop chickenpox have mild disease, regardless of their age at the time of vaccination or the time since vaccination, at least up to 7 to 8 years after vaccination (ie, the vaccine's effectiveness against moderate to severe disease is excellent throughout the period of the study)." The authors final statement is: "It is important to monitor closely the incidence of varicella and the effectiveness of the vaccine over time to determine if a booster dose is needed to improve its effectiveness." Yawn. What a wimpy statement. As I said, let's see how many adults make a conscientious effort to get boosters. And for John: "Financial Disclosures: Dr LaRussa is the recipient of a contract from Merck & Co to perform a varicella-specific PCR assay on blinded samples from recipients of varicella vaccine who have had adverse events potentially related to vaccination. Dr Gershon has received research support for a basic science project from Merck & Co. Drs Shapiro and Gershon served as consultants at a 1-day meeting on vaccine cost-effectiveness sponsored by Merck & Co." Yawn. The now-required conflict(s)-of-interest divulgence (which, in Jonathan's World, automatically prevents/precludes *any* dishonesty by researchers). |
#4
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Chickenpox Vaccine Found to Fade in a Year
"Jonathan Smith" wrote
Now a new study is adding to the debate. Researchers at Yale Medical School reported last week in The Journal of the American Medical Association that the effectiveness of the chickenpox vaccine fades substantially a year after it is administered. The vaccine also appears to confer less immunity to children younger than 15 months. At years 2 through 8, there is NO significant difference in effectiveness by age of vaccination. (Table 4). That may be, but the official schedule is for chickenpox vaccine at 12 months. This new study indicates that it doesn't work very well at that age. |
#5
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Chickenpox Vaccine Found to Fade in a Year
"JG" wrote in message ... (...) "Fades substantially," "decreases significantly".... po-TAY-to, po-TAH-to; to-MAY-to, to-MAH-to... Anal to the core, eh, Jon? Yeah, you can pronounce the words differently, but the difference between "fades substantially" and "decreases significantly" (in a statistical sense) are very different. This is not being anal, but rather pointing out that there is a very different meaning between the phrases. The term "significant" is relatd to the statistical test of difference in RR between Year 1 and subsequent years. The chickenpox vaccine has been approved for use in the United States since 1995. Some experts have questioned whether it should be used at all, arguing that immunizing children just pushes the disease into adulthood, when it is usually more severe. Pushing the disease into adulthood for those who remain unvaccinated, Roger. ...OR those in whom vaccine-induced immunity has significantly (oops, sorry! *substantially*) waned (faded, decreased, whatever). Yet we don't know that the immunity will wane, do we? Aren't you glad that the experts at the CDC are looking into this? I guess the worst case event would be that we need a vaccine every 8 to 10 years, if at all. Jeff However, in the JAMA publication, the authors make no such conjecture nor provide any data on this issue. A quote from the interview in the NYT article: "Up to 8 years, the protection is very good," Dr. Vazquez said. "But will it hold 10, 12, or 20 years down the line? We don't know yet." Hehehe. Good luck getting adults to get boosters; look at the lines we already have to endure for tetanus shots! g It is interesting to note that in Table 3, the effectiveness of the vaccine seems to stabilize at year 3 and shows no significant decline between years 3 and 8 - hovering in the 81 to 84% range. If vaccination is administered at 15 months or older, the overall 8 year composite effectiveness is 88%. Aw, shucks! That's less than the figure--90%--that public health folks claim is necessary to acheive/sustain "herd immunity," isn't it? The sky is falling! At years 2 through 8, there is NO significant difference in effectiveness by age of vaccination. (Table 4). The data show that the effectiveness of a single dose strategy over time (up to 8 years post-vaccination) is about 81-88% depending on various factors and that in the vaccinated but infected cohort, the severity of the disease is generally mild, milder than in unvaccinated. "The vaccine is a success in reducing the risk of varicella in children. This study indicates that at least through the first 8 years after vaccination, the overall effectiveness of live, attenuated varicella vaccine remains good, although breakthrough varicella is not rare. Most vaccinated children who develop chickenpox have mild disease, regardless of their age at the time of vaccination or the time since vaccination, at least up to 7 to 8 years after vaccination (ie, the vaccine's effectiveness against moderate to severe disease is excellent throughout the period of the study)." The authors final statement is: "It is important to monitor closely the incidence of varicella and the effectiveness of the vaccine over time to determine if a booster dose is needed to improve its effectiveness." Yawn. What a wimpy statement. As I said, let's see how many adults make a conscientious effort to get boosters. And for John: "Financial Disclosures: Dr LaRussa is the recipient of a contract from Merck & Co to perform a varicella-specific PCR assay on blinded samples from recipients of varicella vaccine who have had adverse events potentially related to vaccination. Dr Gershon has received research support for a basic science project from Merck & Co. Drs Shapiro and Gershon served as consultants at a 1-day meeting on vaccine cost-effectiveness sponsored by Merck & Co." Yawn. The now-required conflict(s)-of-interest divulgence (which, in Jonathan's World, automatically prevents/precludes *any* dishonesty by researchers). |
#6
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Chickenpox Vaccine Found to Fade in a Year
"Jeff" wrote in message
... "JG" wrote in message ... (...) "Fades substantially," "decreases significantly".... po-TAY-to, po-TAH-to; to-MAY-to, to-MAH-to... Anal to the core, eh, Jon? Yeah, you can pronounce the words differently, but the difference between "fades substantially" and "decreases significantly" (in a statistical sense) are very different. This is not being anal, but rather pointing out that there is a very different meaning between the phrases. The term "significant" is relatd to the statistical test of difference in RR between Year 1 and subsequent years. The chickenpox vaccine has been approved for use in the United States since 1995. Some experts have questioned whether it should be used at all, arguing that immunizing children just pushes the disease into adulthood, when it is usually more severe. Pushing the disease into adulthood for those who remain unvaccinated, Roger. ...OR those in whom vaccine-induced immunity has significantly (oops, sorry! *substantially*) waned (faded, decreased, whatever). Yet we don't know that the immunity will wane, do we? Not definitively, no; there've been conflicting studies. We won't know for sure as long as "wild" cases/outbreaks (which serve to naturally "boost" vaccine-induced immunity) continue to occur. (Rather ironic, don't you think, that vaccinated kids could be benefitting from their unvaccinated friends who contract chickenpox?) Aren't you glad that the experts at the CDC are looking into this? I guess the worst case event would be that we need a vaccine every 8 to 10 years, if at all. And if "we" (I won't; I developed immunity the old-fashioned way!) do need booster shots, how do you propose to get *adults* to cooperate? |
#7
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Chickenpox Vaccine Found to Fade in a Year
"JG" wrote in message ... (...) And if "we" (I won't; I developed immunity the old-fashioned way!) do need booster shots, how do you propose to get *adults* to cooperate? By going to the doctor and getting the vaccine. The same way the they get pneumonia, influenza, tetanus and hepatitis vaccines now. Jeff |
#8
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Chickenpox Vaccine Found to Fade in a Year
"Jeff" wrote in message
... "JG" wrote in message ... (...) And if "we" (I won't; I developed immunity the old-fashioned way!) do need booster shots, how do you propose to get *adults* to cooperate? By going to the doctor and getting the vaccine. The same way the they get pneumonia, influenza, tetanus and hepatitis vaccines now. "They" do? Fact is, "they" *don't*! Only 47% of persons 20 years of age or older have "adequate" tetanus and diphtheria antibody levels (McQuillan GM et al. "Serologic immunity to diphtheria and tetanus in the United States." 2002 May 7;136(9):660-6.) Less than 45 percent of people 65 have had the recommended pneumococcal vaccine (http://www.medhelp.org/NIHlib/GF-209.html). While ~2/3 of those 65 were vaccinated against influenza (1999), only ~1/3 of those 50-64 were (and the rate was lower for Hispanics and African Americans) (http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5103a1.htm). The HBV vaccine isn't even recommended for all adults, just those in specific, higher -risk groups (see http://www.thebody.com/nih/hepatitis...ep_b_candidate). So (again), just how do you propose to get adults to submit to vaccination? |
#9
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Chickenpox Vaccine Found to Fade in a Year
"JG" wrote in message ... "Jeff" wrote in message ... "JG" wrote in message ... (...) And if "we" (I won't; I developed immunity the old-fashioned way!) do need booster shots, how do you propose to get *adults* to cooperate? By going to the doctor and getting the vaccine. The same way the they get pneumonia, influenza, tetanus and hepatitis vaccines now. "They" do? Fact is, "they" *don't*! Only 47% of persons 20 years of age or older have "adequate" tetanus and diphtheria antibody levels (McQuillan GM et al. "Serologic immunity to diphtheria and tetanus in the United States." 2002 May 7;136(9):660-6.) Less than 45 percent of people 65 have had the recommended pneumococcal vaccine (http://www.medhelp.org/NIHlib/GF-209.html). While ~2/3 of those 65 were vaccinated against influenza (1999), only ~1/3 of those 50-64 were (and the rate was lower for Hispanics and African Americans) (http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5103a1.htm). The HBV vaccine isn't even recommended for all adults, just those in specific, higher -risk groups (see http://www.thebody.com/nih/hepatitis...ep_b_candidate). So (again), just how do you propose to get adults to submit to vaccination? By improving health-care insurance in the US so that people could afford to go the clinic for these shots. And improving health-care education. Jeff |
#10
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Chickenpox Vaccine Found to Fade in a Year
"Roger Schlafly" wrote in message .net...
"Jonathan Smith" wrote Now a new study is adding to the debate. Researchers at Yale Medical School reported last week in The Journal of the American Medical Association that the effectiveness of the chickenpox vaccine fades substantially a year after it is administered. The vaccine also appears to confer less immunity to children younger than 15 months. At years 2 through 8, there is NO significant difference in effectiveness by age of vaccination. (Table 4). That may be, but the official schedule is for chickenpox vaccine at 12 months. This new study indicates that it doesn't work very well at that age. Roger - read the article. Your interpretation is wrong. The new study does NOT indicate that "...it doesn't work very well at that age." Here is the direct accurate statement made by the authors in the article: "The vaccine's effectiveness in the first year after vaccination was substantially lower if the vaccine was administered when the child was younger than 15 months than if the child was 15 months or older at the time of vaccination (73% vs 99%, P = .01), although the difference in the effectiveness for these age groups was not statistically significant either for years 2 to 8 or overall (Table 4). Read the article, Roger. Now, here's the question you may want to ask (and then do the math yourself). IF vaccination is delayed by 3 months (from the 12 month visit to the 15 month visit), what is the relative risk in the 12-24 month age time frame for the two groups. Until you answer that question, you cannot make ANY statement as to which vaccination schedule reduces risk of infection with varicella better. The authors do NOT make that calculation. Here is what they do say about this: "However, the improved effectiveness of the vaccine would have to be balanced against both the risk of leaving such children unvaccinated for these 3 months and the risk that some children might not return for vaccination in a timely manner." Read the article, Roger. js |
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