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Health officials on Thursday confirmed the country's first measles death since 2003, and they believe the victim was most likely exposed to the virus in a health facility in Washington state during an outbreak there. The woman died in the spring; a later autopsy confirmed that she had an undetected measles infection, the Washington State Department of Health said in a statement. The official cause of death was announced as "pneumonia due to measles."
According to the U.S. Centers for Disease Control and Prevention, 178 people from 24 states and the District were reported to have measles from Jan. 1 through June 26 of this year. Two-thirds of the cases, the CDC noted, were "part of a large multi-state outbreak linked to an amusement park in California."
Measles were effectively eliminated in the United States in 2000, according to the CDC. Health officials have said that the disease made a comeback recently, in part because of a growing number of adults deciding to delay or abstain from vaccinating their children. Last year brought the highest number of recorded measles cases since 2000, according to the CDC. Earlier this year, President Obama acknowledged the concerns some have about effects of vaccines but said: "The science is pretty indisputable." "You should get your kids vaccinated — it's good for them," Obama said. "We should be able to get back to the point where measles effectively is not existing in this country."
takyon: Celebrity critics recently denounced California's new mandatory vaccine law.
Original Submission
(Score: 1) by khallow on Monday July 06 2015, @02:19AM
You seem to be assuming that measles spreads primarily via direct contact. That is what they assumed in the 1960s, but it is not true. Measles is airborne and that makes the herd immunity concept much more complex.
No, I believe that distinction is wholly irrelevant. For example, the two phenomena mentioned, air-borne contact and the somewhat higher number of contacts, "superspreader" don't actually change the model. You still have to be in near proximity to an infected person in order to catch the disease yourself.
But even if the contact model were somehow in enough error to be irrelevant as a model of the spread of measles, it still is irrelevant to our discussion. Herd immunity is not a consequence of physical contact-only models. It is instead a consequence of the physical reality and backed by decades of observation of measles and other diseases. And the obvious here is that measles has had plenty of opportunity to become a "gigantic epidemic" since vaccination and instead it has nearly vanished despite plenty of reseeding from places that still have measles.
(Score: 0) by Anonymous Coward on Monday July 06 2015, @02:48AM
You are incorrect . The R0 values are used to calculate the percent of the population to be vaccinated for eradication (1/R0). RO depends crucially on the effective contact rate, which, as explained by Langmuir, was assumed to be relatively stable from person to person and day to day. Applying these models to a situation where one person may expose thousands of others in an hour will be misleading. Read the paper, Langmuir explains how *he* made this error in the 1960s when predicting the effectiveness of measles vaccination.
https://en.m.wikipedia.org/wiki/Basic_reproduction_number [wikipedia.org]
(Score: 1) by khallow on Monday July 06 2015, @03:07AM
You are incorrect .
Then where's the argument that I'm wrong? It's not important that contact rate is relatively stable as long as the collective R0 rate is below 1. For example, suppose we consider the case of the one person who infects thousands. As a result, due to 15% immunity rate, only a few hundred will actually show symptoms of measles. In turn, these people will be considerably less infectious than the first person (since superspreaders are by historical observation rare) and infect maybe a few hundred more by the time the bout of infection peters out a few weeks or months later. Your gigantic epidemic causes perhaps a few thousand people in the worst case to show the symptoms of measles.
(Score: 0) by Anonymous Coward on Monday July 06 2015, @05:41AM
It is not R0 that directly matters but the effective reproductive rate R=R0*S/N, where S=# Susceptibles and N=Total Population. When R is less than 1 but the disease is not eradicated, S will constantly increase. "Superspreading" is not (only) a property of the person, but the environment and population. Note that these calculations assume a homogeneously mixing population which may or may not be a good enough approximation of reality.
http://www.ncbi.nlm.nih.gov/pubmed/12176860 [nih.gov]