Thursday, March 22, 2018

ECDC RRA On Measles In EU & Harvard Study On Mumps Vaccine

Credit ECDC


Measles, which was once almost a youth’s `rite of passage’, was declared `eliminated' (defined as `absence of continuous disease transmission for 12 months or more in a specific geographic area') in the United States in 2000, more than 35 years after the introduction of the first measles vaccine in 1963.
During the 1950s the US saw roughly 4 million infections which hospitalized nearly 50,000, and contributed to the deaths of several hundred every year.
Nevertheless, cases still occur, and in 2017 the CDC recorded 118 cases from 15 states and the District of Columbia who contracted the disease. They cite:
  • The majority of people who got measles were unvaccinated.
  • Measles is still common in many parts of the world including some countries in Europe, Asia, the Pacific, and Africa.
  • Travelers with measles continue to bring the disease into the U.S.
  • Measles can spread when it reaches a community in the U.S. where groups of people are unvaccinated.
As noted, measles is less controlled outside of the United States, and Europe continues to report large surges of cases every few years, involving not hundreds - but thousands - of cases.

Since 1999 EU countries have reported nearly 200,000 cases.

 With measles on the rise again early in 2018, the ECDC has published a new RRA (Rapid Risk Assessment).  First we've the ECDC news report, followed by a link to the full 13 page PDF report, after which I'll return with a postscript on new research on the Mumps vaccine.

ECDC Rapid Risk Assessment highlights young adults and healthcare workers as groups that are susceptible to measles, 21 March 2018

21 Mar 2018

ECDC assesses the risk of measles transmission in the EU/EEA in latest rapid risk assessment.

The latest ECDC rapid risk assessment on the risk of measles transmission in the EU/EEA highlights that vaccination coverage and occurrence of cases vary within countries and population groups. It points to the need for systems to identify and vaccinate young adults, who are increasingly affected and therefore increase measles circulation, but who may not be aware of their vaccination status. Finally, ECDC signals the frequency of cases amongst healthcare workers as a matter of concern and suggests that Member States may consider specific interventions to ensure this group is vaccinated.

    Measles cases occur unequally within countries

Data showing the distribution of measles cases within countries (Figure 1) highlights the importance of vaccination coverage of at least 95% of the general population throughout a whole country with two doses of measles-containing vaccine. This is recommended and necessary to ensure that measles circulation is interrupted, and that introduction of measles cases does not result in secondary cases. The availability of data at subnational level allows identification of geographical areas where measles cases are occurring and where targeted actions may be needed to identify unvaccinated individuals, increase coverage rates and carry out response activities.
    Measles increasingly affects young adults who may not be aware of their vaccination status

Some countries have seen an increasing proportion of cases among adults, prompting the need to consider actions to identify people or pockets of susceptible individuals who are incompletely vaccinated or not vaccinated at all. In light of current outbreaks in several EU countries, individuals who have not been vaccinated with two doses of measles-containing vaccine are at risk of contracting and further spreading measles, especially to infants who are too young to be vaccinated and are more vulnerable to complications from the disease.

Healthcare providers should consider recommending vaccination for all eligible individuals who are not immunised, or not fully immunised, in line with national recommendations. Any encounter with the healthcare system should be used as an opportunity for a catch-up vaccination against measles as well as other vaccine-preventable diseases.

    Frequency of measles cases amongst healthcare workers a matter of concern

The frequent occurrence of measles among healthcare workers in several EU/EEA countries is a matter of concern and Member States may consider specific interventions to address this, such as ensuring that all healthcare workers are immune to measles, with proof/documentation of immunity or immunization as a condition of enrolment into training and employment.

ECDC Rapid Risk Assessment highlights young adults and healthcare workers as groups that are susceptible to measles, 21 March 2018

21 Mar 2018

Given the current extent of measles circulation in the EU/EEA, the trend in recent years, and the fact that vaccination coverage for the first and second dose is suboptimal, there is a high risk of continued measles transmission with mutual exportation and importation between EU/EEA Member States and third countries.

Risk of measles transmission in the EU/EEA - EN - [PDF-1.44 MB]

Along with measles, another highly transmissible `childhood' disease - mumps - has been making a comeback in the United States in recent years, and not just in children.  Until 2005 - the mumps vaccine had been credited with reducing the incidence of mumps by about 99%. 

A study, published yesterday in Science Translational Medicine, suggests waning effectiveness of the mumps component in the MMWR vaccine may be behind the dramatic resurgence in mumps cases over the past dozen years. 
They report: `Synthesizing data from six studies of mumps vaccine effectiveness, we estimated that vaccine-derived immune protection against mumps wanes on average 27 years (95% confidence interval, 16 to 51 years) after vaccination.
First a link to the study, and then some excerpts from a Harvard Crimson report on the study.

Vaccine waning and mumps re-emergence in the United States

Joseph A. Lewnard1,* and  Yonatan H. Grad2,3,*

Science Translational Medicine 21 Mar 2018:
Vol. 10, Issue 433, eaao5945
DOI: 10.1126/scitranslmed.aao5945

Harvard Study Links Mumps Outbreaks to Waning Vaccine Immunity 

The recent spate of mumps outbreaks across the country, including one at Harvard, may be due to the waning effectiveness of the mumps vaccine, according to a new study published by two researchers at the Harvard School of Public Health.
Cases of mumps have been on the rise nationwide, according to the Centers for Disease Control and Prevention. In 2017, more than 5,000 people contracted the disease, up from fewer than 1,000 in 2012. College campuses have been hit particularly hard, which experts have previously attributed to the close contact between students.
Grad said he wanted to discover whether the increase in mumps cases was due to a new strain of mumps resistant to the vaccine—or due to the vaccine’s effectiveness wearing off as patients aged. Currently, federal recommendations call for two vaccinations: one between 12 and 15 months of age, and a second between four and six years.
“In our analysis, we saw that waning was consistent with what we were observing, whereas the appearance of a new strain that escaped the vaccine was not,” he said.
In the research paper, the authors suggest a third vaccination around age 18 as a possible means to reduce cases of mumps. The scientists are not the first to consider this idea: In light of recent research, the CDC recommended a third dose for at-risk populations in a January report.
Still, official recommendations do not call for all people to be routinely vaccinated at 18, which the authors say “should be assessed in clinical trials.”

(Continue . . . )

For more on measles, mumps, and the third element of the childhood disease trifecta - Pertussis - you may wish to revisit these blogs:

AMA Statement Supporting Stricter Requirements For School Vaccinations
CDC Telebriefing: Worst US Measles Outbreak In 20 Years

California: Pertussis Rising (Again)

NYC Health Department Investigating Measles Outbreak

ECDC: Risk Assessment On Measles Outbreak Aboard Cruise Ship

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