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.

"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

"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).

"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.

"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).

"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?

"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

"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?

"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

"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