Johns Hopkins experts warn of potentially severe flu season, measles elimination status faces risk

The Johns Hopkins Bloomberg School of Public Health hosted a media briefing today to discuss current and predicted influenza trends, including a potentially severe influenza season, vaccine rates and the potential loss of measles elimination status in the United States.

The event was led by two faculty from the Bloomberg School of Public Health:

William Moss, M.D., M.P.H., professor in the departments of Epidemiology, International Health and Molecular Microbiology and Immunology at the Johns Hopkins Bloomberg School of Public Health, and executive director at the Bloomberg School’s International Vaccine Access Center and Andrew Pekosz, Ph.D., professor and vice chair of the W. Harry Feinstone Department of Molecular Microbiology and Immunology at the Johns Hopkins Bloomberg School of Public Health, and co-director of the Johns Hopkins Center of Excellence in Influenza Research and Response.

The three influenza strains causing current activity are H1N1, IBV and the new H3N2 clade K strain, which may cause an especially severe influenza season in the United States this year. The strain is currently circulating in other parts of the world and has led to an earlier start to the influenza season in the United Kingdom, Japan and Canada.

Pekosz said that the strain has mutations that may allow it to evade some, but not all, of the flu vaccine’s protection.

“It is not too late to get a flu shot,” Pekosz said during the briefing. “We're at the beginning of the influenza season here in the United States, and it takes anywhere from 10 to 14 days for an influenza vaccine to generate that immune response that's going to help you fight off the infection or reduce disease severity. So, it is certainly not too late, especially as we're thinking about holiday gatherings and travel.”

Measles outbreak

The United States reached measles elimination in the year 2000, meaning the disease was no longer spread epidemically within the country. This was achieved through widespread vaccination and outbreak response. However, a resurgence in cases this year could threaten elimination status.

There have been 1,912 measles cases reported in the United States this year. The last time cases were higher was in 1992, before elimination was achieved, when there were just over 2,000 cases reported that year.

A large contributor to the current measles increase is an outbreak in South Carolina. The South Carolina Department of Health has reported 129 cases.

Approximately 11% of measles cases this year have led to hospitalization and there have been three deaths.

“Not surprisingly, 92% of the cases have been in those who are unvaccinated or without a known vaccination status,” Moss said.

Moss also noted that the age distribution of cases is surprising—approximately a quarter of cases have occurred in children under the age of 5 and more than a third of cases have occurred in adults older than 20 years of age.

“It's important to note that the measles outbreaks here in the United States are not the result of the virus mutating, although it does change genetically, but because we have clusters of unvaccinated or under-vaccinated communities where there are susceptible people,” Moss said.

Measles outbreaks are also expensive. An analysis from the International Vaccine Access Center reported that the public health cost per case was approximately $43,000.

The Centers for Disease Control and Prevention (CDC) currently recommends that everyone six months and older should receive a flu vaccine, with rare exceptions.

For measles, the CDC recommends the measles vaccine be given to people ages 12 months or older, given at least 28 days apart.