One unvaccinated child was patient zero of a measles epidemic

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Wakefield-fraudDespite what you think is happening when you read antivaccination blogs, most people in the developed world vaccinate their children. And in the relatively undeveloped world, they are demanding more vaccines so that their children will live longer. In the USA alone, far less than 1% of children, 19-35 months, are completely unvaccinated. The problem, at least in the USA, is that those unvaccinated children tend to be clustered in small geographical areas where individuals who share the typical characteristics of many vaccine deniers tend to live.

The complication is that the herd immunity can break down rather quickly when the vaccination uptake drops below 80-90% in these clusters. And all it takes is one person carrying a vaccine preventable disease from an area, where it is endemic, to then start an outbreak or epidemic very quickly in one of these low vaccine uptake clusters. For a disease like measles, which is very contagious, it jumps from an infected person to unvaccinated individuals quite rapidly, sometimes before public health authorities can contain it. Measles is easily prevented with the MMRV vaccine (which also protects children against mumpsrubella, and chickenpox).

In a recent article published in Pediatrics, researchers investigated a measles outbreak in Minnesota in 2011. The authors, lead by Pamala Gahr of the Minnesota Department of Health, determined that the outbreak began when an unvaccinated 2-year-old travelled to Kenya, where he contracted the measles virus. Upon returning to the United States, the child developed a fever, cough and vomiting, some of the early signs and symptoms of measles. Unfortunately, prior to a diagnosis of measles, the child passed the virus on to three children in a child day-care center and another household member. The measles then spread from individual to individual within a low vaccine uptake area, a Somali immigrant community in the Minneapolis area. Eventually, more than 3,000 people were exposed to the disease. Continue reading “One unvaccinated child was patient zero of a measles epidemic”

Waning whooping cough immunity after DTaP–a new analysis

Protect Your Baby from Whooping Cough.

Despite the fact that over 95% of kindergarteners in the United States are properly vaccinated against whooping cough (Bordetella pertussis) with the DTaP vaccine, there are persistent reports that the rates of whooping cough have risen during the past few years. Several outbreaks, along with an outright epidemic in Washington state, seemed to indicate that the vaccine’s effectiveness is waning faster than expected.

A recently published study in Pediatrics evaluates reports of increased rates of pertussis in the six years after receipt of the fifth (of five) DTaP doses. These reports suggest that waning of immunity to pertussis from DTaP is occurring before the recommended booster age of 11 to 12 years. The researchers tracked more than 400,000 Minnesota and Oregon children using immunization records and state health department whooping cough data. All of those children were born between 1998 and 2003 and received the recommended series of five DTaP shots, the final one usually given at 4-6 years old. Continue reading “Waning whooping cough immunity after DTaP–a new analysis”

The importance of flu surveillance

In 2009, the H1N1 flu pandemic was an influenza pandemic that was first described in April 2009. The virus appeared to be a new strain of H1N1, which was responsible for the 1918 flu pandemic, that arose from a triple reassortment of bird, swine and human flu viruses that then further combined with a Eurasian pig flu virus, leading to the term “swine flu” to be used for this pandemic. Unlike other strains of flu, H1N1 does not disproportionately infect older adults (greater than 60 years), which makes this a characteristic feature of this H1N1 pandemic, and made it especially dangerous to children. The CDC has reported some sobering worldwide statistics for the 2009 H1N1 pandemic, including that between 151,700 and 575,400 people perished worldwide from 2009 H1N1 virus infection during the first year the virus circulated.  Continue reading “The importance of flu surveillance”

Parents put immunocompromised child at risk by not vaccinating sibling

Chickenpox, or Varicella zoster, is a common childhood disease that can result in fairly serious complications such as encephalitis, pneumonia, sepsis, hemorrhagic varicella, and death. Individuals at especially high risk from complications from varicella are immunocompromised, usually from some sort of immunodeficiency or immunosuppression (usually pharmaceutical treatments for cancers or autoimmune diseases). For immunocompromised individuals, it is important that any individuals around them should be vaccinated against common childhood diseases, whether chickenpox or other diseases (mumps, rubella, etc.), because the chances of transmitting these diseases is extremely high and the risk of complications are serious.

The Centers for Disease Control and Prevention reported that a 3 year old Minnesota girl, who was receiving immunosuppressive therapy for juvenile rheumatoid arthritis, was admitted to a hospital after 2 days of a high fever of 102.7°F (39.3°C) and extensive rash, including in her mouth and throat. Neither she nor her younger sibling received the first dose of varicella vaccine (recommended at 12-15 months) because their parents refused the vaccinations as a result of personal beliefs. The child eventually recovered as a result of treatment with intravenous acyclovir (which has more serious potential side effects than the imagined ones for the vaccine). Continue reading “Parents put immunocompromised child at risk by not vaccinating sibling”