(Reuters) - A measles outbreak in California that has been traced to Disneyland in December and renewed a debate over the anti-vaccination movement would be declared over on Friday if no new related cases arise, a public health official said on Thursday.
Officials with the California Department of Public Health are optimistic the outbreak will be declared over as Friday marks the end of a second, 21-day incubation period and there have been no new related cases so far, department spokeswoman Anita Gore said.
"We will be making an announcement tomorrow about the measles outbreak" one way or another, Gore said.
California public health officials have been investigating a multi-state measles outbreak traced to the Disneyland theme park that has sickened 131 people in the state. The outbreak is likely to have started from a traveler who was infected overseas, Gore said.
Measles symptoms can arise as late as two weeks after exposure and bring a fever, followed by a cough, runny nose, red, watery eyes and rash.
The measles outbreak renewed a debate over the anti-vaccination movement in which fears about potential side effects of vaccines, fueled by now-debunked research suggesting a link to autism, have led a small minority of parents to refuse to allow their children to be inoculated.
Some parents also opt not to have their children vaccinated for religious or other reasons.
All U.S. states require certain vaccines for students for diseases such as mumps, rubella, tetanus or polio, but school immunization laws grant exemptions to children for medical reasons, including an inhibited immune system.
Almost all states also grant religious exemptions against immunizations, with 20 states also allowing philosophical exemptions, according to the National Conference of State Legislatures.
On Monday, a Washington state school district pulled from classrooms 143 students who lacked documentation proving they had received required immunizations.
(Reporting by Eric M. Johnson in Seattle; Editing by Will Dunham)