Measles rears its ugly head again. Here are the data and the real bottom line. #1 Don’t worry

A
friend wrote about current TV warnings in Maine re measles: “One kid
tested positive for measles AFTER being inoculated. Now there are
warnings out for anyone who was anywhere near the kid in a variety of
locations and times. Talk about building a fear porn extravaganza!”

Jamie McMahon  ^{1   2} , Ian M Mackay  ^{3   4} , Stephen B Lambert  ⁴

Abstract

Measles
vaccines have been in use since the 1960s with excellent safety and
effectiveness profiles. Limited data are available on detection of
measles vaccine virus (MeVV) RNA in human subjects following
vaccination. Available evidence suggests MeVV RNA can be identified up
to 14 days after vaccination, with detection beyond this rare. In
routine diagnostic testing, we used two real-time reverse
transcription-polymerase chain reaction (RT-rPCR) assays targeting M and
F genes to identify measles virus (MeV) and MeVV RNA. Confirmatory
testing was performed with an N gene RT-rPCR, followed by sequence
confirmation of RT-rPCR positives by semi-nested conventional RT-PCR
assays targeting portions of the N, H, and L genes. We
report detection and confirmation of MeVV RNA from the respiratory tract
of 11 children between 100 and 800 days after most recent receipt of
measles-containing vaccine. These novel findings emphasize the importance of genotyping all MeV detections and highlight
the need for further work to assess whether persistent MeVV RNA
represents viable virus and if transmission to close contacts can occur.

Conflict of interest statement

Jamie McMahon—no conflict; Ian M Mackay—no conflict; Stephen B Lambert—SBL is the current Chair of the National Measles and Rubella Elimination Working Party.

What does the CDC say? How Well Does the MMR Vaccine Work?

MMR
vaccine is very effective at protecting people against measles, mumps,
and rubella, and preventing the complications caused by these diseases.
People who receive MMR vaccination according to the U.S. vaccination
schedule are usually considered protected for life against measles and
rubella. While MMR provides effective protection against mumps for most
people, immunity against mumps may decrease over time and some people
may no longer be protected against mumps later in life. An additional
dose may be needed if you are at risk because of a mumps outbreak.

One dose of MMR vaccine is 93% effective against measles, 78% effective against mumps, and 97% effective against rubella.

Two doses of MMR vaccine are 97% effective against measles and 88% effective against mumps.

MMR
is an attenuated (weakened) live virus vaccine. This means that after
injection, the viruses cause a harmless infection in the vaccinated
person with very few, if any, symptoms before they are eliminated from
the body. The person’s immune system fights the infection caused by
these weakened viruses, and immunity (the body’s protection from the
virus) develops.

Some people who get two doses of MMR
vaccine may still get measles, mumps, or rubella if they are exposed to
the viruses that cause these diseases.

The [Nass] bottom line:

1. Measles is a live virus vaccine that can reproduce and potentially shed for years from vaccinated individuals.

2. 
   We don’t know how many active US measles cases are due to vaccine
   strains because the CDC won’t tell us the results of testing, in order
   to avoid any negative effect on vaccination rates.

3. Vaccination
   initially leads to 93% protection from 1 dose and 97% protection from 2
   doses. Protection wanes over time, yet there are very few measles
   cases in the US yearly (usually under 100) and most can be traced to a case that came in from overseas.

4. The
   last time a child died from measles in the US was 2003. He had had a
   bone marrow transplant and his natural immune system had been
   deliberately wiped out for the transplant. It was never announced
   whether his measles case was due to a vaccine strain or not.

5. Don’t
   worry about measles! It is very rare; if you do get it you will have
   life-long immunity (unless your immune system is wiped out) and it can
   be effectively managed.