News & Views: Updated ACIP Recommendations Related to Mumps and Hepatitis B Published

On January 12, 2018, the Centers for Disease Control and Prevention (CDC) published two updates to vaccine recommendations in their publication, Morbidity and Mortality Weekly Report:

Mumps vaccine — third dose during outbreaks

Some points that may be of interest

• Cases of mumps, incidence, number of outbreaks, proportion of outbreak-associated cases, and number of jurisdictions reporting mumps have been on the rise since 2012.
• Almost 12,000 cases of mumps were diagnosed throughout the U.S. in 2016 and 2017. These numbers are the highest reported in a decade.
• From the beginning of 2016 through mid-2017, 150 outbreaks of mumps occurred. The clinical definition of an outbreak is three or more cases linked by time and place.
• These outbreaks have not been limited geographically to particular areas of the U.S. In fact, more than three-quarters of state health departments have dealt with at least one outbreak in the last year and a half.
• Approximately 50 percent of the outbreaks have occurred in university settings.
• Vaccination status was known for 78 percent of infected individuals and of these, 70 percent had received two doses.
• Less than 3 percent of patients experienced complications. Of those who did, 75 percent experienced orchitis.
• Complication rates were lower in patients who received two doses of vaccine compared with unvaccinated individuals.

About the recommendations

Immunity to the mumps vaccine develops in about 8 to 9 of 10 recipients of two doses; however, protection wanes. When mumps is compared with measles and rubella, limited laboratory evidence suggests lower quantities of antibodies as well as antibodies with lower avidity following either natural infection or vaccination. Additionally, since 2006 the predominant strain of mumps that has been circulating is genotype G, whereas the vaccine is made from a genotype A strain. Neutralizing antibodies directed against genotype G are generated following vaccination, but are present at lower levels than those directed against genotype A.

Over the past several years, experience with a third dose of mumps vaccine in outbreak settings has increased as it was implemented in particular outbreak situations. The third dose was found to be safe and effective. However, data suggests that antibody levels return to near baseline one year after receipt of the third dose, and in the four weeks following vaccination, some side effects were more likely: lymphadenopathy (12 percent), diarrhea (9 percent), headache (7 percent) and joint pain (6 percent). Third dose recommendations during outbreaks were generally well accepted by students and their parents, as reported in surveys of university and public health personnel.

For these reasons, the CDC has recommended a third dose of mumps vaccine during outbreak situations.

Read the complete MMWR article (January 12, 2018, 67(1);33-38).

Hepatitis B vaccine — stronger recommendations related to newborn vaccination

Some points that may be of interest

• New cases of hepatitis B are estimated to be 6.5 times greater than actually reported.
• While national health survey data suggest about 850,000 people in the U.S. are living with chronic infection, studies based on other measures, such as migration and census data, suggest this number may actually be over 2 million.
• About 95 percent of new cases are reported among foreign-born persons with the majority being Asians and Pacific Islanders.
• Although hepatitis B prevention strategies related to birth dose vaccination and vaccination of healthcare personnel have met with success, they remain below Healthy People 2020 targets.
• Hepatitis B virus can be transmitted in the absence of visible blood and can remain infectious on surfaces for at least seven days.
• The virus can be transmitted when infectious blood or body fluids enter a susceptible person through puncture of the skin, exposure to mucosal surfaces or through areas of non-intact skin.
• Infectious body fluids can include semen, vaginal secretions, saliva, tears, bile, cerebrospinal fluids, synovial fluid, pleural fluid, peritoneal fluid, pericardial fluid and amniotic fluid. Body fluids not conducive to transmission include urine, feces, vomit, nasopharyngeal washings, sputum, sweat and breast milk.
• The younger a person is when infected, the more likely they will experience chronic infection. However, immune-suppressed adults and those with diabetes are at increased risk of developing chronic infection compared with their immunocompetent counterparts.
• Chronic infection with hepatitis B includes four phases that do not occur in linear order: immune tolerant, immune active, immune inactive, and reactivation.
• Adults at risk of infection with hepatitis B include injection drug users, heterosexual adults with multiple partners, men who have sex with men, household contacts of individuals with chronic infection, developmentally disabled residents of long-term care facilities, residents of correctional facilities, persons at risk for occupational exposure, individuals on hemodialysis, persons with hepatitis C infection, HIV, diabetes or chronic disease, and travelers to countries with endemic hepatitis B.

About the recommendations

The MMWR article goes on to address prophylaxis following occupational and non-occupational exposures and vaccine recommendations specific for infants, children, adolescents and adults. The recommendations are specific and lengthy; therefore, if you see patients who may require hepatitis B vaccination or who may be exposed to the virus, this issue of MMWR (January 12, 2018. 67(1); 1-31) is worth reviewing directly and bookmarking or printing for easy reference in the future.