Re: Surge in seasonal flu cases possible: CDC (Taiwan)
SEASONAL INFLUENZA, VACCINE MISMATCH - TAIWAN
*********************************************
A ProMED-mail post
<
http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases
<
http://www.isid.org>
******
[1]
Date: Tue 3 Feb 2009
Source: Taiwan Times [edited]
<
http://www.etaiwannews.com/etn/news_content.php?id=855358〈=eng_news>
Flu vaccines not as effective this year as in the past
------------------------------------------------------
Influenza vaccines that proved to be effective late last year have
failed to live up to expectations early this year, the Department of
Health (DOH) said Tuesday [3 Feb 2009]. Chou Jih-haw, Deputy
Director-general of the DOH's Centers for Disease Control, said more
than 3.2 million free flu shots were given to the public in autumn
and winter last year. "Judging from the number of influenza cases in
the fourth quarter of 2008, it was significantly lower than in the
same period the previous year," Chou said. "But this year, tests of
flu viruses on the patients showed that the results have not been as
good as expected," he continued.
Chou said influenza vaccines given in autumn 2008 and this winter
should be effective against the H1N1 and H3N2 viruses, and tests
taken from patients who were inoculated last year proved their
effectiveness. But in January [2009], tests found the vaccines did
not work [were not protective?] on 70 percent of those with H1N1
viruses and 40 percent of those with the H3N2 virus. A vaccine is
considered effective if it controls the virus in 80 percent to 90
percent of those inoculated. Chou would not categorize the vaccines
as ineffective, however, because influenza viruses are "prone to
mutation," meaning that the virus formula for producing vaccines must
be changed on a yearly basis.
A former CDC Director suggested Tuesday that part of the problem may
be that flu viruses tend to strike Taiwan between 6 months and 2
years earlier than European countries and the United States. Su
Ih-jen, Director of the Division of Clinical Research of the National
Health Research Institutes, said that because of the time lag,
influenza vaccines produced by European and American pharmaceutical
makers based on data provided by the World Health Organization could
not keep up with the outbreak of flu in Asia. Su noted that with
close exchanges between Taiwan and China, Taiwan has become an
outpost of influenza outbreaks.
The World Health Organization began to address the issue of different
prevalent viruses in Asia and Europe last April [2008]. Currently, 2
out of 5 major vaccine manufacturers have made inroads into China,
and the production of Asian influenza vaccines "has become a trend,"
he said. Su suggested that the virus in every influenza outbreak is
slightly different, and that "it can show major changes about every 5
years, so the effectiveness of vaccines can diminish."
[Byline: Lilian Wu]
--
Communicated by:
ProMED-mail
<
promed@promedmail.org>
******
[2]
Date: Thu 5 Feb 2009
Source: Taipei Times [edited]
<
http://www.taipeitimes.com/News/taiw.../05/2003435334>
Experts recommend switching to Asian-made flu vaccines
------------------------------------------------------
Anticipating a bigger wave of flu infections caused by a form of the
virus that has become resistant to medication and vaccines, doctors
and academics urged the government to switch to Asian versions of the
flu vaccine. Health officials last week said that with employees
returning to work en masse after the Lunar New Year holiday, flu
infections from increased human interaction in crowded places could
spread fast.
Fear of the flu heightened when the Centers for Disease Control (CDC)
said on Tuesday [3 Feb 2009] that 2 strains of the influenza type A
had mutated slightly and developed resistance to the flu medication
Tamiflu [oseltamivir]. Tamiflu was still 30 percent effective in
fighting the virus in October [2008], but the virus has recently
developed 100 percent resistance against the drug, the CDC said.
"The H1N1 strain [of the flu virus] has mutated into a form that is
70 percent variant from the vaccine, and the H3N2 strain is 40
percent variant," said CDC Deputy Director-general Chou Jih-haw,
referring to the government-funded vaccine inoculation offered free
of charge last year to children, the elderly and other high-risk
groups. CDC statistics showed that influenza type A comprised about
80 percent of all reported cases this winter. The type A H1N1 and
H3N2 strains are currently circulating among flu victims.
"The H1 strain is weaker than the H3 strain. Although the H1 strain
may infect more people [because of its mutation], it is less likely
to make patients critically ill," said Huang Li-min, a pediatrician
at National Taiwan University Hospital.
However, Huang said that he was not sure whether the H1N1 strain
would mutate into a form that could result in critical conditions. He
recommended that doctors prescribe 2 types of flu medication
simultaneously, such as Tamiflu [oseltamivir] combined with
amantadine, another type of flu treatment. This way, in case the
virus strain has developed resistance to certain drugs, the
medication may still be effective in controlling the disease, he said.
The flu virus undergoes minor changes from time to time, and a major
variant emerges about every 5 years, said Su Ih-jen, Director of the
National Health Research Institute's division of clinical research.
Su urged the government to switch from European-made vaccines to
Asian-made ones, saying the latter was more "up to date" with new
virus strains. "In 2005, we published research showing that the virus
strains in Taiwan were 2 years ahead of Europe," he said. "We should
be using Asian versions of the vaccine to stay up to date with the
disease." In response, Chou said the CDC would assess the need to
switch to the vaccines used in China, which he said would be more
effective in combating the ever-changing virus.
[Byline: Shelley Huang]
--
Communicated by:
ProMED-mail
<
promed@promedmail.org>
[Vaccine mismatch is being invoked to explain the relatively poorer
protective response obtained by vaccination in Taiwan in the current
year compared to that obtained in the preceding year. This is
attributed to progressive change in the epidemic virus as a
consequence of accumulation of mutations in the viral genome.
According to the above reports previous research in Taiwan has
suggested that: "virus strains in Taiwan were 2 years ahead of
Europe." On this basis it is proposed that vaccines more in harmony
with requirements in south and southeast Asia should be developed locally.
Increasing resistance of current epidemic strains to the antiviral
drugs Tamiflu and amantadine in Taiwan is considered to be another
consequence of the mutability of the virus rather than a consequence
of the enhanced use of these drugs in clinical practice. In contrast
a recent study in Europe (Kramarz et al., Eurosurveillance, Vol. 14,
Issue 5, 2009
(<
http://www.eurosurveillance.org/View...rticleId=19112>)
based on analysis of prescription data concluded that while the
precise relationship between oseltamivir [Tamiflu] use and resistance
of influenza A(H1N1) to oseltamivir remains uncertain, the available
data do not suggest a link between the rapid rise in the proportion
of the resistant A(H1N1) and the use of oseltamivir in Europe. - Mod.CP]
[A map showing the location of Taiwan is available at:
http://www.worldatlas.com/webimage/countrys/asia/tw.htm> -CopyEd. EJP]
[see also:
2008
----
Influenza vaccine 2009 (02): S. hemisphere
20080923.3009
Influenza vaccine 2009: S. hemisphere
20080922.2988
Influenza vaccine 2008/2009 - N. hemisphere
20080805.2404
Influenza virus, 2007/2008 vaccine mismatch
20080209.0529
Influenza virus, vaccine response: RFI
20080209.0528
2007
----
Influenza: update & vaccine composition
20070810.2607
Influenza vaccine 2007/2008 - N Hemisphere
20070215.0566]
-
http://apex.oracle.com/pls/otn/f?p=2..._ID:1000,76025
------
...................cp/ejp/mpp
