When a case of measles surfaced suddenly in Nassau County two weeks ago, disease detectives went back on the trail of an ancient foe for the second time in 19 months and a decade after the common childhood virus had been declared eliminated in the United States.
An hour away from Nassau's borders, Rockland County health authorities were grappling with another scourge from the past - a major mumps outbreak 42 years after development of a mumps vaccine. More than 300 cases have been diagnosed since August.
Long forgotten childhood diseases, already making a comeback in Europe, have cropped up in significant numbers here. Alarmed by the re-emergence of contagious diseases, health officials are taking steps to shore up herd immunity - the safety net that protects whole communities because most inhabitants are vaccinated.
"We can't let our guard down," said Dr. Guthrie Birkhead, a deputy commissioner with the New York State Department of Health. "There are parents who say they've never heard of anybody in their community catching one of these diseases. But that's because we create herd immunity through vaccination rather than through disease."
Threats, experts say, increasingly confront the herd: A demographic shift among people going unvaccinated - it's no longer the poor but the middle- and upper-middle classes; the importation of mumps and measles from new hot zones in Europe and Israel; and legislative attempts to make it easier for children to avoid vaccines.
Legislators have allowed vaccine exemptions based on religious or medical grounds. Some supporters of these exemptions argue the state requires too many vaccinations for school-aged children and that some parents fear health side effects.
Between 1999 and 2008, the number of students granted religious exemptions from vaccines - the only allowable nonmedical waiver for school-aged children in New York State - more than doubled even as the total number of children starting school declined slightly.
There is no single religion or religious belief that dominates among parents who obtain religious exemptions, said Gary Krasner, founder of the Coalition for Informed Choice, a Queens group that helped craft New York legislation to make it easier for parents to obtain religious waivers.
According to Krasner, a school district decides on an exemption application on a case-by-case basis.
Herd safety net
Herd immunity is generally strong in New York, meaning that in most places, including Nassau and Suffolk, at least 90 percent of children are immunized against childhood diseases, Birkhead said. But he acknowledged the herd safety net has been compromised in Rockland, where about 85 percent are immunized.
When breaches occur in the herd defense, he said, any forgotten disease can surface.
"Herd immunity is only as strong as the vaccine coverage in a given area," said Dr. Paul Offit, developer of the rotavirus vaccine and director of the Vaccine Education Center at Children's Hospital of Philadelphia. "Although immunization rates nationwide are quite high there are areas where it is very low and those are the areas where outbreaks can occur, and have occurred," he said.
Of the Rockland cases, Birkhead asked: "Was this a case of vaccine failure or a failure to vaccinate?" Health officials there are offering families a third booster dose of mumps vaccine - a first in New York State - to bring the outbreak under control. "It's possible that two doses of vaccine and 85 percent protection in the herd is not enough to prevent infection."
In addition, experts have long known that the mumps portion of the MMR is not as strong as the other two.
In Nassau, the health department acted aggressively to snuff out measles. Nassau disease detectives sought out all public venues where the infected 1-year-old had been over a four-day period then publicized them.
Herd immunity is vital, said Dr. Sharon Nachman, a pediatric infectious disease specialist at Stony Brook University Medical Center, because it protects people who cannot be vaccinated, primarily anyone with transplants or immune deficiencies.
The Rockland mumps outbreak has roots in Britain. A boy contracted mumps while visiting England, kindling New York's resurgence of the infection when he returned.
Many European parents stopped vaccinating their children after publication of a widely discredited 1998 study that suggested the measles, mumps and rubella vaccine was linked to autism, said Dr. Pascal Imperato, dean of public health at SUNY Downstate in Brooklyn. Indeed measles and mumps incidents in many developed countries rose.
The Nassau measles case involved a baby who contracted it in Ireland. Another Nassau case in 2008, part of a state- and nationwide outbreak, involved a baby who caught measles while visiting Israel.
Many Long Island parents have resisted vaccines, some saying the government recommendation of more than 25 are too many. And they have a Long Island legislator pushing for a philosophical exemption.
Assemb. Marc Alessi (D-Wading River) said parents should have some choice. Alessi is the author of a philosophical exemption bill that would allow children to avoid mandatory shots based on their parents' conscientious objections. Alessi said even if it never passes - it has been stalled in committee for two years - he wants to form a state task force to determine whether the current number of required childhood vaccinations is necessary.
"I honestly think vaccines are important," said Alessi, who has had his two children vaccinated. "But there are other parents who have anxiety. They're saying too much too soon could be damaging."
Assemb. Richard Gottfried (D-Manhattan) who chairs the assembly's health committee, said he supports making it easier to obtain a religious exemption because it's "outrageously impossible" to get one in some parts of the state. Gottfried opposes philosophical exemption measures.
In Middle Island, Christine Heeren has secured an exemption for her school-age son.
"I support vaccination choice," she said. "I am not going to tell anyone what to do about vaccinating their children."
Heeren's son, Michael, 10, has an autism spectrum disorder. He does not have to show evidence of vaccination to attend school. "I did a religious waiver; it's public record." Heeren's religion is Universalism.
Setauket parents Charles and Stella Massimo also do not believe in the value of vaccines and want their triplets, Christopher, Steven and Elaina, to remain vaccine-free.
The Massimos say they are dealing with a 21st century epidemic of autism. "My two boys have autism and we believe that vaccinations were part, but not totally the cause," Charles Massimo said.
Stella Massimo added the family was recently jolted by a demand from their children's school: "We just got a letter from the school about diphtheria vaccination saying it's mandatory. We're trying to find a way to avoid it."Childhood diseases and their symptoms
What is it? A highly communicable respiratory disease, caused by a virus and typified by a splotchy rash that spreads from the hairline, then covers face and trunk
Possible complications: Encephalitis, pneumonia
Seriousness: Kills an estimated 197,000 people globally annually. No deaths in the United States since being declared eliminated in 2000.
Vaccine: Measles vaccine available since 1963
Recent Activity: Upsurge in developed countries. Significant U.S. outbreak in 2008; one case in Nassau County two weeks ago
What is it? An acute, highly contagious infection of the salivary glands, caused by a virus, that results in marked facial swelling.
Possible complications: Hearing loss; male infertility
Seriousness: People rarely die of mumps
Recent activity: Making a comeback in Britain. Between 1980 and 1999 there were no recorded cases of mumps there, but between 2000 and 2008 there were 86,912. Cases have since declined, but are still prevalent. In the United States, 2006 outbreak with more than 1,000 cases. More than 300 cases in Rockland County since August.
Vaccine: Mumps vaccine available since 1967
What is it? Also known as whooping cough because of the sound of a sufferer's cough. Highly communicable respiratory disease, caused by the bordetella pertussis bacterium. Can last 6 to 10 weeks
Possible complications: Rib fracture from violent coughing; pneumonia; seizures; malnutrition due to constant coughing.
Seriousness: Infection can be fatal if untreated.
Recent activity: In 1976, 1,010 cases reported nationwide. In recent years, average 11,000 per year. In New York State, 453 cases were reported in 2008.
Vaccine: Available since the late 1940s. Now administered as the "P" in the DtAP shot
What is it? Acute contagious viral infection that causes a blistering rash
Possible complications: Usually itchy discomfort for a few days, but rare cases can lead to encephalitis; older people can develop painful shingles. Women who develop it during pregnancy can pass the infection to fetus.
Seriousness: Before vaccine introduction, 10,000 children hospitalized annually in the United States; 100 U.S. deaths
Recent activity: Chickenpox incidence not monitored in New York.
Vaccine: Available since 1995.