The physician who reported to Pundita readers last week on swine flu in England has waded through the CDC's Prevention and Control of Seasonal Influenza with Vaccines handbook, which was released on July 31, 2009. Here he summarizes the main points and adds his comments:
At 56 pages, including 10 pages of journal references, the handbook is quite a tome. Unfortunately, it is only marginally helpful:
• Injected influenza vaccine, 2009-2010 season is recommended for virtually everyone over 6 months of age: particularly for 6 months to 4 years of age and those above 65 years, plus those with chronic respiratory tract diseases (including asthma), diabetes, heart disease, immunologically active diseases and all women pregnant or likely to be within the next several months.
• Inhaled vaccine (Med-Immune) is for all of those between 4 and 60 years of age, but to be avoided by those in pregnancy or the listed diseases.
• There is some appeal scientifically for the inhaled, live virus vaccine over the killed, injected vaccine in terms of the immunity created. However, this is mostly theoretical at this time and there are concerns about live virus vaccines among those pregnant or with the listed chronic illnesses.
• Vaccines work with an efficiency between 50-90% in preventing clinical influenza and even with "wrong vaccine virus" there is some apparent usefulness.
• Influenza infections cause everything from symptoms of the common cold to death from overwhelming viral pneumonia, so numbers involving influenza are always subject to lots of interpretative arguments.
• Vaccination is especially important for health care providers and those who take care of young children or elderly or ill persons at home. It prevents cases of illness among those being helped, as well as among the helpers.
• Vaccination with the 2009-2010 vaccine will NOT contain the H1N1 Mexican swine flu strains. It is advised by the CDC that "everyone" as noted above should have this vaccine. (But it is likely that most of the influenza season of 2009-2010 in the USA will be from the H1N1 Mexican flu strains and that vaccine will probably be late in coming—maybe not until after the worst is over with the fall 2009 influenza.)
• Many people DO have some immunity to "new" influenza strains, but not enough immunity to keep from getting moderately ill with something "new." This creates great problems with statistics, but it is great for the person infected.
I believe this covers the most important aspects of this lengthy discussion.
I am suspicious of an early "flu season" in 2009 (September to early October) with most from the Mexiflu [2009 H1N1 swine flu].
The major rationale for going ahead and using the produced 2009-2010 vaccine is this concept for cross-over immunity, which won't prevent illness but may greatly reduce the severity.
On the other hand, they never push for non-pharmacological measures and this tome excludes discussion of those. Masks, for example are not "enough" to prevent infections, even if they greatly reduce infections.
My take on this year's flu vaccine: It will be about as useful as wearing a fresh mask every time you go out in public. Actually, the mask may be better -- but in the absence of absolutely preventing infection [the CDC] won't endorse its use.
I have not seen anything [from the CDC] discouraging the use of masks, as much as encouraging hand-washing/alcohol-hand-sanitizers and nothing much beyond that. Absolutely weird stance on these two segments of the flu story.
DocJim
DocJim -- Thanks for the summary. See my upcoming post today about a new CDC-funded study on the utility of face masks during an influenza epidemic. The study results throw light on the CDC's fence-sitting about masks.
Pundita
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