The CDC is preparing to review its guideline for measles and healthcare workers, as the once-eradicated childhood infection spreads in ongoing outbreaks in the U.S. and Europe.

“There have been several outbreaks involving hospitals in recent years, so we thought that measles was probably important to get to next,” says David Kuhar, MD, a medical officer in the CDC’s Division of Healthcare Quality Promotion who is spearheading development of the guidelines. “It is labor-intensive and expensive when you have these outbreaks. I think a lot of these recent measles outbreaks have involved healthcare workers who got measles, and some of them had been immunized previously. That raises a lot of questions about how to appropriately approach measles, especially in the outbreak setting.”

Indeed, an outbreak reported last year found that even clinicians with history of measles vaccination have about a 3% change of breakthrough, with the investigators recommending N95 respirators be worn to examine and care for patients with suspected or confirmed measles.1

Kuhar was also co-author of a review study2 that found that 78 reported measles cases resulted from transmission in U.S. healthcare facilities in 2001-2014. That includes 29 healthcare workers who were infected from occupational exposure, one of whom transmitted measles to a patient. The economic impact of preventing and controlling measles transmission in healthcare facilities was $19,000–$114,286.

“Of the 29 HCP who were infected with measles, 19 (65.5%) had adequate presumptive evidence of measles immunity which includes: written documentation of vaccination with 2 doses of live measles or MMR vaccine administered at least 28 days apart, laboratory evidence of immunity, laboratory confirmation of disease, or birth before 1957,” Kuhar and colleagues wrote. “In addition to the 29, there were 5 measles cases among HCP who were either infected outside of work or had an unknown transmission setting. Although we did not include these 5 HCP, they had the potential to pass on measles to their patients or other healthcare providers.”

Indeed, community outbreaks threaten to bring measles in via patients or healthcare workers. As this report was filed, Minnesota state health officials reported an ongoing measles outbreak in the Minneapolis area had reached 79 cases. Of those, 71 people had not received MMR vaccine.

Most of the infections were in children and adolescents. The unvaccinated were primarily people in the Somali community, some of whom fear adverse effects of vaccination. The connection between MMR and autism has been completely debunked, but an anti-vaccination movement in the U.S. is one reason a disease declared eradiated in the country in 2000 is still causing disruptive and expensive outbreaks.

“Healthcare workers, students in post-high school educational institutions, or international travelers should have two documented vaccinations with a live measles (for example, MMR) vaccine separated by at least 28 days and administered after the person turned 1 year old,” Minnesota state health officials advised.

With the peak summer travel season under way, the CDC is reminding travelers to Europe and other global destinations to take steps to protect themselves against measles. More than 14,000 cases of measles have been reported in Europe since January 2016, according to the European Centre for Disease Prevention and Control. In the past year, 35 people across Europe have died from the disease, according to the World Health Organization.

Pertussis Resurges

Another childhood vaccine-preventable disease is resurging. As of July 27, 2017, Indiana had already doubled its number of cases of pertussis seen last year, and state health officials were urging immunization with Tdap in predicting the case count would continue to climb.

“In the first half of 2017, 136 cases of pertussis have been confirmed in Indiana,” the department reported. “During the same period in 2016, the state saw 66 cases. Because pertussis tends to be cyclical, [we] expect to continue to see an increase in cases this year.”

The health department emphasized the need for the series of Tdap shots for the public, particularly those that may be exposed to infants highly vulnerable to the infection. Though there are signs of gradual improvement, healthcare workers are still woefully under-immunized against pertussis, putting vulnerable patients such as infants at risk, the CDC reports.3

“We want all healthcare workers up to date with their Tdap vaccine, but especially those who work and interact with young infants,” says Jennifer L. Liang, DVM, MPVM, a co-author of the study and a medical epidemiologist in the CDC Division of Bacterial Diseases. “They are too young to even begin receiving the vaccination.”

The CDC recommends that healthcare workers be vaccinated with Tdap (tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis) to protect themselves and vulnerable patients. The CDC study assessed Tdap vaccination coverage in healthcare worker surveillance for the years 2012-2014, the most recent data available. The internet panel surveys revealed Tdap vaccination coverage among healthcare personnel (HCP) was 34.8% in 2012; 40.2% in 2013; and 42.4% in 2014, Liang and co-authors report.

“Based on the findings, we see that most healthcare personnel are not receiving the Tdap vaccination, which leaves them vulnerable to getting pertussis and spreading it to their patients,” Liang says. “We’re hopeful that we will continue to see the trend increasing, and we encourage employee health professionals to have strategies in place similar to what they do with flu vaccine campaigns to help increase coverage.”

To prevent pertussis in healthcare settings, the CDC recommended in 2005 that HCP receive a single dose of Tdap vaccine at an interval as short as two years from the last dose of tetanus and diphtheria toxoids (Td). In 2011, the CDC expanded the Tdap recommendations to all healthcare workers, regardless of age and time since their most recent Td vaccination. Some confusion about the guidelines may be part of the reason for the low uptake of vaccine, the CDC concedes.

“A booster is not recommended at this time,” Liang says. “The recommendation is that healthcare workers receive one dose of the Tdap vaccine. At this time, it is a one-lifetime dose. The one exception is pregnant women. They should have a Tdap vaccine every pregnancy.”

REFERENCES

  1. Gohil SK, Okubo S, Dickey L, et al. Healthcare Workers and Post-Elimination Era Measles: Lessons on Acquisition and Exposure Prevention. Clin Infect Dis 2016; 62:166-172.
  2. Fiebelkorn AB, Redd SB, Kuhar DT. Measles in Healthcare Facilities in the United States during the Post-elimination Era, 2001-2014. Clin Infect Dis 2015;61(4):615–618.
  3. Srivastav A, Black CL, Lu P, et al. Tdap Vaccination Among Healthcare Personnel, Internet Panel Survey, 2012–2014. Am J Prev Med 2017; May 23. [Epub ahead of print].