What is the vaccine?
The H1N1 vaccine will not prevent seasonal flu
http://www.medscape.com/viewarticle/709468
Who gets infected?
http://www.cdc.gov/H1N1FLU/surveillanceqa.htm
Side effects of the flu vaccine?
Nichol KL, Lind A, Margolis KL, et al. “The effectiveness of vaccination against
in!uenza in healthy, working adults”. NEJM. 1995; 333:889-93.
http://content.nejm.org/cgi/content/full/333/14/889?ck=nck
Who should get the Swine Flu vaccine?
The rationale rests on the heavy burden that influenza imposes on the population and the benefits of vaccination. For example, reductions in cases, admissions to hospital, mortality of elderly people in families with children, contacts with healthcare professionals, antibiotic prescriptions, and absenteeism for children and household contacts are the main arguments for extending vaccination to healthy children aged 6-23 months in the United States.2
http://www.bmj.com/cgi/content/full/333/7574/912
# American Academy of Pediatrics Committee on Infectious Diseases. Recommendations for influenza immunization of children. Pediatrics 2004;113: 1441-7.[Abstract/Free Full Text]
http://www.bmj.com/cgi/ijlink?linkType=ABST&journalCode=pediatrics&resid=113/5/1441
On the basis of single studies, the World Health Organization estimates that "vaccination of the elderly reduces the risk of serious complications or of death by 70-85%."5
http://www.bmj.com/cgi/content/full/333/7574/912
# World Health Organization. Influenza vaccines. WHO position paper. Wkly Epidemiol Rec 2002;77: 230-40.[Medline]
http://www.bmj.com/cgi/external_ref?access_num=12143096&link_type=MED
A systematic review of the incidence of influenza in people up to 19 years' old reported a seasonal variability of 0-46%; during a five year period the average incidence was 4.6% in this age group. During a period of 25 years the incidence was 9.5% in children under 5.6
http://www.bmj.com/cgi/content/full/333/7574/912
: People aged 65 or more
: Patients in institutions who have chronic medical conditions
: Adults and children with chronic disorders of the cardiovascular and respiratory systems (including asthma but excluding hypertension)
: Adults and children who have been treated in hospital in the preceding 12 months for a range of conditions (for example, diabetes or haemoglobinopathy) Adults and children with conditions that compromise respiratory function or handling of infected secretions Children aged 6 months to 18 years being treated with aspirin
: Women who are pregnant during the influenza "season"
: Children aged 6-59 months
: Adults aged 50-64 years
: Carers and household contacts (including children) of those in the above risk categories and of children aged 0-59 months
Healthcare workers
http://www.bmj.com/cgi/content/full/333/7574/912
CONTRAVERSY
The second problem is either the absence of evidence or the absence of convincing evidence on most of the effects at the centre of campaign objectives (table 2). In children under 2 years inactivated vaccines had the same field efficacy as placebo,8 and in healthy people under 65 vaccination did not affect hospital stay, time off work, or death from influenza and its complications.9 Reviews found no evidence of an effect in patients with asthma or cystic fibrosis, but inactivated vaccines reduced the incidence of exacerbations after three to four weeks by 39% in those with chronic obstructive pulmonary disease.12 13 19 All reviewers reported small data sets (such as 180 people with chronic obstructive pulmonary disease13), which may explain the lack of demonstrable effect.
http://www.bmj.com/cgi/content/full/333/7574/912
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MERCURY & THIMERSOL
http://www.cdc.gov/mmwr/preview/mmwrhtml/rr58e0724a1.htm#tab1
http://content.nejm.org/cgi/content/full/357/13/1281
http://www.ncbi.nlm.nih.gov/pubmed/15342825
http://www.immunizationinfo.org/thimerosal_mercury_detail.cfv?id=3
http://www.pbs.org/now/science/mercuryinfish.html
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EFFICACY & EFFECTIVENESS
Effectiveness vs Efficacy
http://beta.medicinescomplete.com/journals/fact/current/fact0403a02t01.htm
CDC effectiveness data
http://www.cdc.gov/Flu/professionals/acip/efficacycomparison.htm
http://www.cdc.gov/mmwr/preview/mmwrhtml/rr58e0724a1.htm#tab1
live vaccines showed an efficacy of 79% (95% confidence interval (CI) 48% to 92%) and an effectiveness of 33% (95% CI 28% to 38%) in children older than two years compared with placebo or no intervention.
Inactivated vaccines had a lower efficacy of 59% (95% CI 41% to 71%) than live vaccines but similar effectiveness: 36% (95% CI 24% to 46%).
In children under two, the efficacy of inactivated vaccine was similar to placebo.
# Smith S, Demicheli V, Di Pietrantonj C, Harnden AR, Jefferson T, Matheson NJ, et al. Vaccines for preventing influenza in healthy children. Cochrane Database Syst Rev 2006;(1):CD004879.
Estimates of vaccine efficacy or effectiveness among children aged ≥6 months have varied by season and study design. In a randomized trial conducted during five influenza seasons (1985--1990) in the United States among children aged 1--15 years, annual vaccination reduced laboratory-confirmed influenza A substantially (77%--91%) (87).
A limited 1-year placebo-controlled study reported vaccine efficacy against laboratory-confirmed influenza illness of 56% among healthy children aged 3--9 years and 100% among healthy children and adolescents aged 10--18 years (108).
A randomized, double-blind, placebo-controlled trial conducted during two influenza seasons among children aged 6--24 months indicated that efficacy was 66% against culture-confirmed influenza illness during the 1999--00 influenza season but did not reduce culture-confirmed influenza illness significantly during the 2000--20 influenza season (109).
http://www.cdc.gov/mmwr/preview/mmwrhtml/rr58e0724a1.htm
A case-control study conducted during the 2003--04 season found vaccine effectiveness of 49% against laboratory-confirmed influenza (107). An observational study among children aged 6--59 months with laboratory-confirmed influenza compared with children who tested negative for influenza reported vaccine effectiveness of 44% in the 2003--04 influenza season and 57% during the 2004--05 season (110). Partial vaccination (only 1 dose for children being vaccinated for the first time) was not effective in either study. During an influenza season (2003--04) with a suboptimal vaccine match, a retrospective cohort study conducted among approximately 30,000 children aged 6 months--8 years indicated vaccine effectiveness of 51% against medically attended, clinically diagnosed pneumonia or influenza (i.e., no laboratory confirmation of influenza) among fully vaccinated children and 49% among approximately 5,000 children aged 6--23 months (106). Another retrospective cohort study of similar size conducted during the same influenza season in Denver but limited to healthy children aged 6--21 months estimated clinical effectiveness of 2 TIV doses to be 87% against pneumonia or influenza-related office visits (102). Among children, TIV effectiveness might increase with age (87,111). A systematic review of published studies estimated vaccine effectiveness at 59% for children aged >2 years but concluded that additional evidence was needed to demonstrate effectiveness among children aged 6 months--2 years (112).
http://www.cdc.gov/mmwr/preview/mmwrhtml/rr58e0724a1.htm
When the vaccine and circulating viruses are antigenically similar, TIV prevents laboratory-confirmed influenza illness among approximately 70%--90% of healthy adults aged <65 years in randomized controlled trials (121--124).
http://www.cdc.gov/mmwr/preview/mmwrhtml/rr58e0724a1.htm
Efficacy or effectiveness against laboratory-confirmed influenza illness was 47%--77% in studies conducted during different influenza seasons when the vaccine strains were antigenically dissimilar to the majority of circulating strains (117,119,121--124).
However, effectiveness among healthy adults against influenza-related hospitalization, measured in the most recent of these studies, was 90% (125).
http://www.cdc.gov/mmwr/preview/mmwrhtml/rr58e0724a1.htm
The only randomized controlled trial among community-dwelling persons aged ≥60 years reported a vaccine efficacy of 58% (CI = 26%--77%) against laboratory-confirmed influenza illness during a season when the vaccine strains were considered to be well-matched to circulating strains (159). Additional information from this trial published separately indicated that efficacy among those aged ≥70 years was 57% (CI = -36%--87%), similar to younger persons. However, few persons aged >75 years participated in this study, and the wide confidence interval for the estimate of efficacy among participants aged ≥70 years included 0 (160).
http://www.cdc.gov/mmwr/preview/mmwrhtml/rr58e0724a1.htm
you will see that using laboratory-confirmed infection, either live or inactivated flu virus has an efficacy of 40% - 45%.
http://scienceblogs.com/effectmeasure/2009/07/transmission_pathogenicity_vir_1.php
Live influenza vaccine and inactivated vaccine provided similar protection against laboratory-confirmed infection (for live vaccine: VE(S) = 41%, 95% confidence interval (CI): 15, 66; for inactivated vaccine: VE(S) = 43%, 95% CI: 8, 79).
Live vaccine had a higher efficacy for illness given infection (VE(P) = 67%, 95% CI: 24, 100) than inactivated vaccine (VE(P) = 29%, 95% CI: -19, 76), although the difference was not statistically significant. VE(SP) for the live vaccine was higher than for the inactivated vaccine. VE(I) estimates were particularly low for these influenza vaccines. VE(SP) and VE(C) can remain high for both vaccines, even when VE(I) is relatively low, as long as the other 2 measures of vaccine efficacy are relatively high.
An analysis of the double-blind, randomized controlled trial conducted among 1,602 children aged 15–71 months by Belshe et al. (13, 14) found that the VESP [vaccine efficacy for infection-confirmed influenza illness] for the absolute efficacy of live vaccine was 92% (95% CI: 89, 94).
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2638553/?tool=pubmed
In a double-blind, randomized controlled trial of 1,616 children aged 6 to less than 36 months, Vesikari et al. (15) reported a VESP [vaccine efficacy for infection-confirmed influenza illness] for the absolute efficacy of live vaccine as 85% (95% CI: 74, 92).
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2638553/?tool=pubmed
Another double-blind, randomized controlled vaccine trial of 3,174 infants and young children found that the efficacy of live vaccine against homologous strains was similar (VESP = 73%, 95% CI: 63, 81) (16).
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2638553/?tool=pubmed
In a community-based, nonrandomized field trial using surveillance cultures to estimate VESP [vaccine efficacy for infection-confirmed influenza illness] for the absolute efficacy of live vaccine in children aged 18 months to 18 years, Halloran et al. (17) reported an efficacy of 79% (95% CI: 51, 91) against homologous strains of influenza.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2638553/?tool=pubmed
========================================ODDS
Odds of contracting some form of influenza in the US
Population of US divided by number of cases per year
314659000 / 39,332,375 (12.5% of population)
= 1 in 8
Odds of contracting some form of influenza IF YOU HAVE KIDS in the US
Population of US divided by number of cases per year
314659000 / 132,156,780 (42% attack rate)
= 1 in 2
Odds of being hospitalized by the flu in the US
Population of US divided by hospitalisations per year
314659000 / 200,000
=1 in 1573
Odds of dying from Influenza in the US
Population of US divided by number of deaths per year
31465900 / 36,000
= 1 in 8740
Odds of contracting Swine Flu in the US
Population of US divided by number of cases per year
314659000 / 57602
= 1 in 5462
Odds of contracting Swine Flu in The US (2)
Pop. of US divided by estimated number of cases per year
314659000 / 6,105,536
= 1 in 51
http://www.cdc.gov/h1n1flu/estimates_2009_h1n1.htm
Odds of dying from Swine Flu in the US
Population of US divided by number of deaths per year
31465900 / 1123
= 1 in 280,195
http://www.cdc.gov/Flu/keyfacts.htm
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* CDC estimates that between 14 million and 34 million cases of 2009 H1N1 occurred between April and October 17, 2009. The mid-level in this range is about 22 million people infected with 2009 H1N1.
* CDC estimates that between about 63,000 and 153,000 2009 H1N1-related hospitalizations occurred between April and October 17, 2009. The mid-level in this range is about 98,000 H1N1-related hospitalizations.
* CDC estimates that between about 2,500 and 6,000 2009 H1N1-related deaths occurred between April and October 17, 2009. The mid-level in this range is about 3,900 2009 H1N1-related deaths.
Odds of contracting Swine Flu in The US (3)
Pop. of US divided by estimated number of cases per year
314659000 / 22,000,000
= 1 in 14
http://www.cdc.gov/h1n1flu/estimates_2009_h1n1.htm
Odds of being hospitalized with Swine Flu in the US (3)
Population of US divided by number of hospitalized per year
31465900 / 98,000
= 1 in 3,210
Odds of dying from Swine Flu in the US (3)
Population of US divided by number of deaths per year
31465900 / 3,900
= 1 in 80,681
In the United States a person aged 50–64 is nearly ten times more likely to die an influenza-associated death than a younger person, and a person over age 65 is over ten times more likely to die an influenza-associated death than the 50–64 age group.[55] Vaccination of those over age 65 reduces influenza-associated death by about 50%.[56][57]
http://en.wikipedia.org/wiki/Influenza_vaccine#Effectiveness_of_vaccine
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