Recent Vaccine-Preventable Disease Research Presented by CDC EIS Officers Highlights the Value of Vaccines

"Vaccines are one of the greatest success stories in public health. Through use of vaccines, we have eradicated smallpox and nearly eliminated wild polio virus. The number of people who experience the devastating effects of preventable infectious diseases like measles, diphtheria, and whooping cough is at an all-time low," according to the Centers for Disease Control and Prevention (CDC).

Officers of the CDC’s Epidemic Intelligence Service (EIS) presented the results of their recent research on May 5, 2016 in the Vaccine-Preventable diseases session of the 65th Annual Epidemic Intelligence Service (EIS) Conference in Atlanta, Georgia. A brief summary of the information they presented is below:

"In resource-limited countries, nearly 1,000,000 children die of pneumonia each year, and in the Dominican Republic, 45% of children in the country's main children's hospital with pneumonia also have effusion," Sana S. Ahmed, MD, noted in her talk. She and her colleagues compared the clinical characteristics and outcomes of pneumonia with effusion in that country's children under age 15 before and after a 13-valent pneumococcal conjugate vaccine (PCV13) was introduced into the country in 2013.

The researchers compared data from 121 pre-PCV13 cases from June 2009 through July 2011 with data from 105 post-PCV13 cases from June 2014 through July 2015. Pneumococcus was identified by culture, polymerase chain reaction on pleural fluid and serotyping, and comparisons were made using chi squared.

Details available for 105 post-PCV13 cases included that the median patient age was 2 years, 18% of patients developed sepsis, 46% needed supplemental oxygen, 8.6% went to an intensive care unit and 11% died. Coverages for the first, second and third PCV13 doses were 84%, 73%, and 28%, respectively. In both pre- and post-PCV-13 surveillance periods, the proportions of pneumococcus cases were similar: 51.2% pre-PCV13 and 56.2% post-PCV13 (P=0.54). The proportion of pneumococcal pneumonia caused by PCV13-serotypes held steady among children old enough to receive the vaccine: 92% pre-vaccine and 96% post-vaccine (P=1.0). Vaccinating more children may improve disease rates and outcomes, the authors wrote.

Srinivas A. Nanduri, ­­MD, and his group found that, while group B streptococcal (GBS) infections are the leading cause of neonatal sepsis and meningitis in the United States, a trivalent maternal vaccine may significantly cut infection rates.

The authors analyzed GBS disease trends in infants and estimated the potential impact of a vaccine being developed that targets serotypes Ia, Ib and III, classifying GBS infections in infants 0 to 6 days of age as early-onset disease (EOD) and infections in infants 7 to 90 days of age as late-onset disease (LOD).

Between 2006 and 2014, 1,188 EOD cases and 1,255 LOD cases were detected. Overall EOD incidence dropped from 0.38 cases per 1,000 live births in 2006 to 0.27 in 2010 (P=0.014) but remained stable at 0.26/1,000 live births since 2011. LOD incidence held steady at 0.29/1,000 live births in 2009 and 0.30/1,000 in 2014. Serotype data were available for 1,548 (73.5%) of 2,105 EOD and LOD infants. A maternal trivalent vaccine targeting serotypes Ia, Ib and III might be expected to cover 63% of EODs and 82% of LODs, the authors suggest.

Winston E. Abara, PhD, MPH, MBBS, and his co-authors studied whether, in US-Affiliated Pacific Islands (USAPI), where HBV is endemic, high vaccine coverage corresponded with a large drop in prevalence of current infection over time.

In the mid-1980s, the USAPI introduced universal infant hepatitis B vaccination. The researchers evaluated that program's progress by calculating current HBV infection prevalence and vaccination coverage among children in the USAPI who were under ten years of age and born in the 1980s, 1990s, and 2000s.

They used demographic and serologic data from seroprevalence surveys of children throughout the USAPI in 1985, 1986, 1991, 1995, 2000, 2005, 2010, 2011 and 2015, and they classified positive hepatitis B surface antigen serology as current HBV infection. Current HBV infection prevalence and vaccination coverage were estimated by descriptive statistics and one-way analysis of variance.

Overall, 1,283 children were born in the 1980s; 840 in the 1990s; and 2,339 in the 2000s. As vaccination rates climbed (76.4% [1980s]; 88.7% [1990s]; 97.5% [2000s]; P < 0.0001), current HBV prevalence dropped (10.1% [1980s]; 1.9% [1990s]; 0.3% [2000s]; P < 0.0001). The researchers advised continued vaccination to eliminate HBV in the USAPI.

Temitope A. Folaranmi, MBChB, MPH, MPP, and his co-authors assessed the risk of rare but serious meningococcal disease among men who have sex with men (MSM) and found that MSM, especially those with HIV, are at greater risk than non-MSM.

The researchers reviewed all cases among males aged 18 through 64 that had been reported to the National Notifiable Disease Surveillance System between January 2012 and June 2015, and they collected MSM status and potential risk factors from state health departments. Using 2012 census data. They compared annualized incidence rates among MSM vs men not known to be MSM (non-MSM).

Overall, 74 cases were reported among MSM and 453 among non-MSM. Among MSM, meningococcal disease risk was 4.0 times the risk in non-MSM; and among HIV-infected MSMs, the risk was 9.8 times the risk in HIV-uninfected MSM. Among MSM with known information, 52 (48.1%) used recreational drugs, 63 (31.7%) used tobacco and 31 (45.2%) had multiple or anonymous sexual partners. Pulse-field gel electrophoresis and whole genome sequencing displayed distinct phylogenetic groups associated with MSM clusters.

Policymakers need to consider that, while vaccination may lower disease risk among MSM, vaccine immune response in people with HIV is weak, the absolute risk of disease is low, and the need for booster doses is likely, the authors advised.

Emily A. Fisher, MD, and her colleagues evaluated the effectiveness of a mass vaccination campaign during an outbreak of invasive serogroup B meningococcal disease (ISBMD) caused by Neisseria meningitidis at the University of Oregon (UO) in Eugene. ISBMD has a 10% fatality rate, and between January and May, 2015, 7 people connected with UO contracted the disease and 1 died.

They conducted a retrospective cohort study of UO undergraduates to find the groups at highest risk, and they surveyed vaccine recipients at vaccination clinics to measure uptake and evaluate the effectiveness of their message.

Freshmen were more likely than nonfreshmen (risk ratio [RR]: 8.2; 95% confidence interval [CI]: 1.5—44.7), and fraternity and sorority members were more likely than nonmembers (RR: 10.2; CI: 1.9–55.6), to contract ISBMD. Overall, 6,362 vaccinees (roughly 90% of clinic attendees) completed surveys. The 29% of registered freshmen and 21% of fraternity and sorority members who attended a mass vaccination were more likely to do so than nonfreshmen (RR: 2.1; CI: 2.0–2.2) and nonmembers (RR: 1.2; CI: 1.2–1.3). Students preferred getting information about the program by email (90%); and their most common reasons for getting vaccinated were concern about becoming ill (65%) and requests from parents (55%). The authors recommend using email and engaging parents to improve vaccination rates.

Lorraine L. Janeczko, MPH, is a medical science writer who creates news, continuing medical education and feature content in a wide range of specialties for clinicians, researchers and other readers. She has completed a Master of Public Health degree through the Department of Epidemiology of the Johns Hopkins Bloomberg School of Public Health and a Dana Postdoctoral Fellowship in Preventive Public Health Ophthalmology from the Wilmer Eye Institute, the Johns Hopkins University School of Medicine and the Bloomberg School.

SOURCE: EIS 2016 Conference Program, pp 106-108: Concurrent Session O1: Vaccine-Preventable Diseases

Studies Presented:

Sana S. Ahmed, MD, EIS officer, National Center for Immunization and Respiratory Diseases, Pneumonia with Pleural Effusion Among Children Two Years After 13-Valent Pneumococcal Conjugate Vaccine Introduction — Santo Domingo, Dominican Republic, June 2014—July 2015

Srinivas A. Nanduri, MD, EIS officer, National Center for Immunization and Respiratory Diseases, Trends in Group B Streptococcal Infections Among Young Infants and the Potential Impact of a Maternal Vaccine in the United States, 2006—2014

Winston E. Abara, PhD, MPH, MBBS, EIS officer, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Hepatitis B Virus Elimination: Evaluating Disease Reduction After Implementation of Infant Vaccination — U.S.-Affiliated Pacific Islands, 1985—2015

Temitope A. Folaranmi, MBChB, MPH, MPP, EIS officer, National Center for Immunization and Respiratory Diseases, Meningococcal Disease Among Men Who Have Sex with Men — United States, 2012—2015

Emily A. Fisher, MD, EIS officer, Division of Scientific Education and Professional Development, Evaluation of Risk Factors and Effectiveness of Mass Vaccination Campaign in Response to Serogroup B Meningococcal Disease Outbreak — University of Oregon, 2015