The Flu and Your Health

December 12, 2010 | by

It’s the gift-giving season. However, there’s one gift this time of year you don’t want to give or get: the flu virus. Flu season runs from November to April, with most cases occurring between late December and early March. About 10-20% of people get the flu every winter [1]. In children, the number is even higher with up to 40% of children becoming clinically ill due to the influenza virus.

Health Highlights – January 29th, 2010

January 29, 2010 | by

Health Highlights is a biweekly summary of particularly interesting articles from credible sources of health and medical information that we follow & read. For a complete list of recommeded sources, see our links page.

Health Highlights

Refusing Immunizations Increases Risk of Chickenpox in Children

January 20, 2010 | by
ResearchBlogging.org

According to a new study published in the journal Archives of Pediatrics & Adolescent Medicine, children of parents who refuse vaccines are over eight times more likely to get chickenpox compared to fully immunized children [1]. The study, funded by the National Institute of Allergy and Infectious Diseases (NIAID), it is the first to assess the relationship between parental vaccine refusal and the risk of chickenpox in children.

Varicella zoster virus (VZV) is a virus of the herpes family that causes chickenpox in children. In adults, the virus can cause both shingles, a painful skin rash characterized by a band of blisters that wrap around the torso from the middle of the back to the chest, and postherpetic neuralgia, persistent nerve pain that occurs after skin rash and blisters heal. VZV or chickenpox is a classic childhood disease and is one of the most commonly refused childhood vaccines due to perceptions by parents and healthcare providers that it is the least severe of all vaccine-preventable diseases. More than 90% of cases occur in children less that 15 years of age, with the highest age-specific incidence occurring during the preschool and kindergarten years (ages 3 – 6) [2]. The varicella vaccine, introduced in the U.S. in 1995, has reduced the incidence of disease and hospitalizations due to chickenpox by 90% [3].

chickenpox-immunization

To establish the relationship between refusing vaccination and the risk of VZV infection, researchers used electronic health records of more than 86,000 children who were members of Kaiser Permanente, an integrated managed care organization, in Colorado between 1998 and 2008 to examine data on both vaccination and disease status.

They identified 343 patients with an ICD-9 (International Classification of Diseases, 9th Revision) diagnostic code of varicella infection. Patients were excluded if they met any of the following criteria:

  • a history of varicella illness rather than acute infection
  • diagnosis within 14 days of varicella vaccination
  • diagnosis by telephone only
  • reason for lack of vaccination not documented in the medical records
  • medical contraindications to varicella vaccination

Thus, 133 of the 343 patients were clinically diagnosed with varicella vaccination and evaluated further. Each case was matched by age, sex and length of healthcare enrollment to 4 randomly selected controls; 39 children were excluded from this control population because they did not have immunization records. Thus, the final control population consisted of 493 children.

Among the 133 cases, seven patients (5%) had parents who refused all varicella immunizations compared to 3 (0.6%) among the controls. Parental refusal of varicella vaccination was strongly associated with medical record-verified varicella illness, resulting in an increased risk of chickenpox requiring medical care (odds ratio, 8.6) compared with children who were vaccinated. This means that children whose parents refuse varicella vaccination were 8.6 times more likely to get chickenpox compared to fully immunized children.

The percentage of attributable risk in patients whose parents refused the vaccine was 99.4%. This is the portion of cases attributable and avoidable to VZV infection, suggesting that all seven of the unvaccinated varicella cases in the study were due to vaccine refusal. According to Jason Glanz, Ph.D., an epidemiologist at Kaiser Permanente’s Institute for Health Research and lead author on the study [4]:

Varicella isn’t necessarily a mild illness, and it’s important for parents to know that choosing not to vaccinate their children not only places their child at risk for infection requiring medical care, but also places members of the community at risk. This study adds to the body of information showing that the benefits greatly outweigh the risks of this safe vaccine.

The study has several limitations: the study population was taken from a single managed healthcare plan and geographical area, which may limit the generalizability of the findings; there may be a diagnostic bias, as physicians are more likely to make a diagnosis of chickenpox in children who are unvaccinated; there was not enough statistical power to evaluate the association between vaccine refusal and varicella infection on a yearly basis; and mild cases of varicella that did not come to medical attention would have been overlooked, over- or under-estimating the effect of vaccine refusal on the risk of varicella infection.

Vaccine recommendations

The best way to prevent chickenpox is through vaccination. Universal varicella immunization has reduced annual morbidity, mortality and hospitalizations attributable to chickenpox by more than 80% [5], and reduced healthcare costs by 97% [6].

The CDC recommends the following chickenpox (varicella) vaccination schedules:

  • All healthy children 12 months through 12 years of age should have two doses of chickenpox vaccine, with the first dose administered at age 12 — 15 months and the second dose at age 4 –6 years (preferably before entering pre-kindergarten, kindergarten or first grade).
  • Adolescents and adults 13 years of age and older who have never had chickenpox or the vaccine should receive two doses of the varicella vaccine, administered 4 — 8 weeks apart.

The CDC recommends the shingles (varicella-zoster) vaccine (Zostavax) for all adults 60 years of age and older who have healthy immune systems. Note that Zostavax is not approved for people younger than age 60.

References

  1. Glanz et al. Parental refusal of varicella vaccination and the associated risk of varicella infection in children. Arch Pediatr Adolesc Med. 2010 Jan;164(1):66-70. DOI: 10.1001/archpediatrics.2009.244
    View abstract
  2. Finger et al. Age-specific incidence of chickenpox. Public Health Rep. 1994 Nov-Dec;109(6):750-5.
    View abstract
  3. Guris et al. Changing varicella epidemiology in active surveillance sites–United States, 1995-2005. J Infect Dis. 2008 Mar 1;197 Suppl 2:S71-5.
    View abstract
  4. Refusing Immunizations Increases the Risk of Varicella Illness in Children, Kaiser Permanente Study Finds. Kaiser Permanente press release. 2010 Jan 4.
  5. Roush SW, Murphy TV, Vaccine-Preventable Disease Table Working Group. Historical comparisons of morbidity and mortality for vaccine-preventable diseases in the United States. JAMA. 2007;298(18):2155-2163.
    View abstract
  6. Zhou et al. An economic analysis of the universal varicella vaccination program in the United States. J Infect Dis. 2008 Mar 1;197 Suppl 2:S156-64.
    View abstract

What You Need to Know About the H1N1 Vaccine

October 1, 2009 | by
H1N1 vaccine

We’ve received a number of questions and concerns about the swine flu and the H1N1 vaccine. Indeed, a new survey by the Harvard School of Public Health finds that six in ten adults are not “absolutely certain” they will get the H1N1 vaccine, citing concerns over side effects, lack of perceived risk and belief that they could receive medication if they do get sick [1]. Just over half of parents surveyed report being “absolutely certain” they well get the vaccine for their children. To help disseminate credible information on the H1N1 vaccine and provide additional sources for review, we’ve put together a list of questions and answers addressing what you need to know about the H1N1 vaccine.

YouTube as a Source of Health Misinformation

February 3, 2008 | by

social network
The Internet is rapidly transforming healthcare. Not only is it creating new connections for the access, sharing and exchange of information, it is cultivating a new level of knowledge among patients, enabling them to have input into decisions about their healthcare. Indeed, 80% of adult Americans say they have researched at least one specific health topic, either information on exercise and fitness, or information about immunizations or vaccines, online at some point [1]. A 2003 WebMD study found that consumers spent more time researching health information online than any other media source [2].

Unfortunately, with all the reliable health information online, an equal or greater amount of misinformation also exists. An article in the Economist last year discussed the exponential increase in user-generated content, encouraged by sites such as YouTube, Facebook and Wikipedia, and its affect on healthcare [3]. The article concluded by quoting a professor at Harvard Medical School:

Many doctors, he says, “don’t get the wisdom of crowds.” But he thinks the combined knowledge of a crowd of his patients would be far greater than his own.

However, the trouble with “The Wisdom of Crowds” or “Crowdsourcing” is that a group of people connected by a network doesn’t necessarily mean they will work together as or more effectively than in traditional organizations.

… Quite simply, not all crowds are wise.

In his book “The Wisdom of Crowds”, James Surowiecki wrote the following [4]:

The smartest groups are made up of people with diverse perspectives who are able to stay independent of each other. Independence doesn’t imply rationality or impartiality. You can be biased and irrational, but as long as you’re independent, you won’t make the group any dumber.

A study published in the Journal of the American Medical Association examined “The Wisdom of Crowds” by evaluating YouTube as a source of information on immunization [5]. University of Toronto researchers searched YouTube using the keywords “vaccination” and “immunization”, and measured users interaction with the videos using view counts and viewer reviews indicated by the star-rating system. Scientists evaluated 153 videos:

  • 73 (48%) of the videos were positive, meaning the central message of the video supported immunization (e.g. described the benefits and safety of immunizing, described immunization as a social good, or encouraged people to receive immunizations).
  • 49 (32%) of the videos were negative, meaning the central message of the video portrayed immunization negatively (e.g. emphasized the risk of immunization, advocated against immunizing, promoted distrust in vaccine science, made allegations of conspiracy or collusion between supporters of vaccination and manufacturers).
  • 31 (20%) of the videos were ambiguous, meaning the video contained either a debate or was ambivalent.

Although almost half the videos were positive and only 20% were negative, compared with positive videos, negative videos were more likely to receive a rating, had a higher mean star rating and more views.

The videos were then rated for scientific accuracy based on the 2006 Canadian Immunization Guide, which has recommendations similar to those from the American Centers for Disease Control and Prevention. None of the positive videos contradicted the Guide. However, nearly half of the negative videos (22 of 49; 45%) carried messages that did contradict the Guide. These included messages that general childhood immunization can cause autism and that scentific research supports the link between thimerosal and autism. However, perhaps the most striking data from the study was that, among the positive videos, public service announcements received the lowest mean ratings and the fewest views.

The authors comment at the end of the study that:

The video ratings and view counts suggest the presence of a community of YouTube users critical of immunization.

And that community of YouTube users is growing rapidly. According to a December 2007 report by the Pew Internet & American Life Project, the typical share of internet users going to video sites was nearly twice as large as it was in December 2006 [6].

With the pervasiveness of blogs and RSS on the Internet today, content has become a commodity. Indeed, “information overload” tends to be everywhere. With too much information and not enough time, capturing an audience’s attention is paramount. Everyone has heard the cliché: “Content is King”. In the age of Web 2.0 and YouTube, packaging, not content, has clearly become King. This is the message public health authorities and others trying to communicate accurate health information need to pay attention to: it’s not just what you say, it’s how it’s presented.

References

  1. Fox S and Fallows D. Internet Health Resources: Health searches and email have become more commonplace, but there is room for improvement in searches and overall Internet access. Pew Internet & American Life Project. 2003 July 16.
  2. Research Reveals That Internet Has Become Primary Means by Which Consumers Access Health Information. WebMD press release. 2003 Feb 10.
  3. Health 2.0. The Economist. 2007 Sep 6.
  4. Suroweicki J. (2004). The Wisdom of Crowds: Why the Many Are Smarter Than the Few and How Collective Wisdom Shapes Business, Economies, Societies and Nations. Boston: Little, Brown, Boston.
  5. Keelan et al. YouTube as a source of information on immunization: a content analysis. JAMA. 2007 Dec 5;298(21):2482-4. DOI: 10.1001/jama.298.21.2482
    View abstract
  6. Rainie L. Increased Use of Video-sharing Sites. Pew Internet & American Life Project. 2008 Jan 9.