Bàn
thêm cho vui, H1N1 flu vaccine
Tiến sĩ Bùi Quốc Quang,
Chuyên Khoa Độc Chất Học (Toxicology)
Yes, the swine flu vaccine has been approved by the US FDA (Sept 15, 2009)
as well as by the Australian authority, two European countries, China,
and perhaps by many other countries. In the US, million and million doses
of the vaccine should be available by mid-October 2009 and millions will
insist on getting the vaccination in hope of preventing a "pandemic
flu". Does getting an approval by the FDA means safety and efficacy?
In most instances, the answer is yes and the US FDA (as well as similar
agencies worldwide) deserves our appreciation and trust. However, despite
FDA’s careful evaluation of applications, we still face with recalls,
bans, removals, black-box warnings, etc. due to unanticipated adverse
health effects that could not be detected due to the limitations of toxicology
studies and restrictions of clinical trials. My dear colleagues, there
is always a risk even with approved products.
We should understand that getting approval for swine flu vaccine from
the FDA means that the vaccine is made properly and meets specific manufacturing
and quality standards that are currently applied to regular flu vaccine.
Note that the FDA did not mention that approval is based on proof of efficacy
and safety. Vaccine manufacturers insist that insertion of a new strain
in an existing flu vaccine should not substantially affect the safety
or level of protection offered. FDA concurs and agrees that H1N1 is just
a variant of the "regular" flu, hence the H1N1 flu vaccine should
be "as safe as the regular flu vaccine ". The FDA allows itself
to "fast tract" the approval of H1N1 flu vaccine based on substantial
safety information from regular vaccine and not from swine flu vaccine.
In other words, approval is based on assumption and extrapolation of information
from regular vaccine. FDA’s approval decision is probably correct and
scientifically justified but FDA also warns for "post-market surveillance"
of rare side effects (neurological) that may occur with the vaccine. FDA
does not want to see a second "1976 neurological outbreak" potentially
linked to swine vaccine. There is always a substantial risk with fast
tract approval.
You may argue that clinical trials were conducted with the swine flu vaccine.
Yes, there are. But vaccine clinical trails are completely different from
those with pharmaceutical agents. Pharmaceutical clinical trials are based
on efficacy against an existing medical condition and safety is determined
by the allowable dosage level. Vaccine clinical trials are based on immunologic
responses and not on a medical condition (i.e., vaccine is for prevention
and not treatment), hence efficacy comes into question. The proposed dose
for swine flu vaccination is still not settled and that affects safety.
There is always a risk.
It seems to me that nowadays many issues related to our health are erroneously
influenced by unqualified individuals or groups. Many of the views and
perceptions are expressed by celebrities (talk-show hosts, actors and
actresses, etc.), political groups and legislators, i.e., individuals
who intentionally do not distinguish between harm, hazard and risk. The
“individual concern” turns into a “perceived risk”, which is then hyped
by the media. The media is a social amplification of risk and floods the
general population with uncertainties, probabilities, consequences, dread,
and fatalities. Through the media, the individual concern and the individual
“perceived risk” are transformed into an “unacceptable risk”, which suddenly
becomes a general population concern or “societal concern”. Everybody
now demands actions, answers, and solutions from regulatory agencies.
The “fast track” approval of swine H1N1 flu to ease a “perceived risk”
is no different. A fast track approval must be at the expenses of other
factors, hopefully not efficacy and safety.
To vaccinate or not to vaccinate, that’s the question? It’s up to each
individual’s concern and acceptable risk tolerance. Risk perception is
essentially multidimensional and personalistic, with a particular risk
of hazard meaning different things to different people and different things
in different contexts. As health professionals and scientists, our approach
to risk must be different from the lay person. Risk to us means “objective
risk” or “numerical risk” based on statistic and estimation. We have the
obligation to communicate risk in a non-judgmental fashion and based on
facts not hypes.
To me, it’s a risk and benefit judgment and I am not going to vaccinate
against swine flu. I recognize the existence of H1N1 flu but I do not
anticipate a pandemic swine flu.
The risk of "ăn vụng bị vợ bắt gặp qủa tang" is more than getting swine flu, so I am saving the vaccination money for "soda hột gà, bổ tỳ bổ vị để còn sửa soạn xáp la cà" .
Until the next time, stay healthy.
Bùi quốc Quang
Copyright, 2009. Muốn phổ biến bài viết này, cần
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