Not a fan of Pan

At a recent hearing on SB277 State Senator Block asked if the CDC or AMA had data about the probability or likelihood of large or huge outbreaks occurring if a certain number of children remained unvaccinated. The answer, based on what history tells us, is that at current rates we are well protected: outbreaks are currently rare rare and huge ones are unheard of.

Measles was considered eradicated* nation-wide (eradicated meaning any small outbreaks that occurred over that time frame resulted from imported cases) with rates lower than or about equal to what we have in California today under current laws in place. 2015 MMR vaccination rate in California is 92.6%

2001-08 nation-wide vaccination rates for MMR from CDC Pink Book 12th edition

2001 - 91.4

2002 - 91.6

2003 - 93.0

2004 - 93.0

2005 - 91.5

2006 - 92.4

2007 - 92.3

2008 - 92.1

There were clusters of lower immunity throughout this period just as there have always been and are today

As to what would happen if this bill passed, there is no metric allowing us to foresee a future with a one or two percent increase in vaccination rates. Historically a 1-3% fluctuation in national rates has occurred randomly from year to year with no demonstrable effect on the number of cases.

One would need a well-funded, peer-reviewed study to even begin to try to measure the impact of  a small increase in vaccination rates. Anything Senator Pan could produce in a matter of days would be nothing more than a guess. I don’t think we want to pass a bad bill on a guess.

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Senator Pan keeps talking about things getting worse because we are not stopping the curve of increasing exemptions. But as he well knows, exemptions are no longer rising. Exemptions fell 20% last year and they fell even more dramatically in the clusters of under-vaccination he so often refers to. This is a result of his own bill - AB 2109 - which passed in 2012. The L.A Times reports:

http://www.latimes.com/local/california/la-me-immunization-data-20150123-story.html

“Statewide, the rate of vaccine waivers for kindergartners entering school in the fall declined to 2.5% in 2014 from 3.1% in 2013. Bigger declines were seen in districts with some of the larger vaccine exemption rates.

In the Santa Monica-Malibu Unified School District, the rate fell from 14.8% to 11.5%; Capistrano Unified in south Orange County declined from 9.5% to 8.6%; Beverly Hills Unified declined from 11.9% to 5%; and Laguna Beach Unified declined from 15.1% to 2%, according to The Times' analysis.”

The last two areas mentioned achieved astonishingly large drops in exemptions. With Beverly Hills exemptions falling 54% to and those in Laguna Beach falling 86%

Overall MMR vaccination rates are stable and at or near record highs

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Almost 7% of children are admitted to school without vaccines on a conditional basis. These children are far more numerous than those who have personal belief exemptions. This bill does not address those conditional exemptions

According to press reports:

"These students may lawfully enter kindergarten on a “conditional basis,” with some, but not all, of their required shots. The condition is that they’ll get up to date soon."

http://blogs.kqed.org/stateofhealth/2015/02/02/not-just-un-vaccinated-under-vaccination-also-a-problem-statewide/

This is another reason eliminating the personal exemption will have almost no practical effect on measles risks

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Senators Marty Block and Loni Hancock asked:

Q: If my child is vaccinated and another is not, what are the chances my child will get the measles

A: Since there is a 90% chance transmission would occur if the child were not vaccinated, and the vaccine is 99% effective your  vaccinated child's odds of getting the measles would be less than 1%

Sources:

“Measles is so contagious that if one person has it, 90% of the people close to that person who are not immune will also become infected.”

http://www.cdc.gov/measles/about/transmission.html

http://www.cdc.gov/vaccines/pubs/pinkbook/meas.html
“Studies indicate that, if the first dose is administered no earlier than the first birthday, greater than 99% of persons who receive two doses of measles vaccine develop serologic evidence of measles immunity”