Molecular Epidemiology of Measles in California, United States-2019.

In 2019, the United States (US) experienced the highest number of measles importations and cases in the postelimination era. More than a quarter of imported cases entered the US through California. Measles surveillance efforts in California resulted in the identification of 26 importations, 6 outbreaks, and 72 cases in 2019. Only genotype B3 and D8 measles strains were detected. Genotype-specific differences were noted in the incidence of vaccine failures, hospitalizations, and severe complications among cases. A targeted whole genome sequencing approach provided higher-resolution discrimination between epidemiologically linked and sporadically introduced strains than conventional N450 sequencing. Our report underscores the importance of ensuring appropriate measles vaccination status, especially prior to international travel to measles-endemic regions, and highlights the value of a strong measles surveillance system in minimizing outbreaks and preserving measles elimination status in the US.

Increased Risk of Late-onset Streptococcus pneumoniae Meningitis in Adults With Prior Head or Spine Surgeries.

In a case-control study within the Kaiser Permanente Northern California adult population, prior head or spine surgery was associated with increased Streptococcus pneumoniae meningitis outside of the postoperative period (no prior head or spine surgery; odds ratio, 6.0 [95% confidence interval, 1.9-18.6]). Among the cases, only 33.3% had received any prior pneumococcal vaccinations.

Barriers to Receipt of Prenatal Tetanus Toxoid, Reduced Diphtheria Toxoid, and Acellular Pertussis Vaccine Among Mothers of Infants Aged <4 Months with Pertussis - California, 2016.

Vaccination with tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine is recommended for all pregnant women to protect infants who are too young for vaccination from severe pertussis-related outcomes (1-3). However, Tdap vaccine coverage among pregnant women remains suboptimal in California (4). California mothers whose infants developed pertussis in 2016 and their prenatal care providers were interviewed to ascertain possible reasons for low Tdap vaccine coverage. Mothers who were offered Tdap vaccination on-site during a routine prenatal visit were more likely to be vaccinated than were mothers who were referred off-site for vaccination. Mothers insured by Medicaid were less likely to receive Tdap vaccine than were mothers with private insurance, even when the vaccine was stocked on-site. Nearly all vaccinated mothers received Tdap vaccine in their prenatal clinic. Incorporating Tdap vaccination into routine prenatal care visits is an effective means to increase prenatal Tdap vaccination coverage.

Effectiveness of Prenatal Tetanus, Diphtheria, and Acellular Pertussis Vaccination on Pertussis Severity in Infants.

BACKGROUND: All US women are recommended to receive a tetanus, diphtheria, and acellular pertussis (Tdap) vaccine at 27-36 weeks gestation during each pregnancy to reduce the risk of pertussis to their infants. The impact of this strategy on severity of disease among infected infants has not been evaluated. METHODS: We use a retrospective cohort study design evaluating whether pertussis-infected infants born in 2011-2015 whose mothers received Tdap vaccine during pregnancy had less severe pertussis, resulting in a lower risk of hospitalization or intensive care unit admission compared with infants born to unvaccinated mothers. RESULTS: Infected infants of vaccinated mothers were significantly less likely to be hospitalized and had significantly shorter hospital stays compared with infants born to unvaccinated mothers, after adjustment for chronological and gestational age and receipt of diphtheria and tetanus toxoids and acellular pertussis vaccine. Unadjusted and adjusted vaccine effectiveness for preventing hospitalization among infants with pertussis was 72% (95% confidence interval [CI], 49%-85%) and 58% (95% CI 15%-80%), respectively. No infants born to vaccinated mothers required intubation or died of pertussis. CONCLUSIONS: Infants with pertussis whose mothers received Tdap during pregnancy had a significantly lower risk of hospitalization and intensive care unit admission and shorter hospital stays. Prenatal Tdap vaccination is a critical strategy for reducing the morbidity and mortality from pertussis.

Effectiveness of Prenatal Versus Postpartum Tetanus, Diphtheria, and Acellular Pertussis Vaccination in Preventing Infant Pertussis.

BACKGROUND: Most severe and fatal cases of pertussis occur in infants <8 weeks of age, before initiation of the primary pertussis vaccine series. Women are recommended to receive tetanus, diphtheria, and acellular pertussis (Tdap) vaccine at the start of the third trimester of each pregnancy to optimize transplacental transfer of antibodies to the fetus. This recommendation was made by the Advisory Committee for Immunization Practices based on immunogenicity data, and no studies in the United States have yet evaluated the effectiveness of this strategy in reducing pertussis incidence in infants. METHODS: We evaluated a cohort of mothers with documented Tdap vaccination histories in the California Immunization Registry to determine whether infants whose mothers received Tdap vaccine at 27-36 weeks gestation had a lower risk of pertussis at <8 weeks of age than infants born to women who received Tdap vaccine within 14 days post partum. RESULTS: Tdap vaccination received at 27-36 weeks gestation was found to be 85% (95% confidence interval, 33%-98%) more effective than postpartum Tdap vaccination at preventing pertussis in infants <8 weeks of age . Vaccination at 27-36 weeks gestation was more effective at preventing pertussis in infant than vaccination during the second trimester. CONCLUSIONS: Tdap vaccination at 27-36 weeks gestation was 85% more effective than postpartum vaccination at preventing pertussis in infants <8 weeks of age. Efforts should be made by prenatal care providers to provide Tdap vaccine to pregnant women during routine prenatal visits at the earliest opportunity between 27 and 36 weeks gestation.

A Population-Based Study of Recurrent Symptomatic Bordetella pertussis Infections in Children in California, 2010-2015.

BACKGROUND: Natural infection with Bordetella pertussis is thought to result in 4-20 years of immunity against subsequent symptomatic pertussis infection. However, these estimates are based on studies in unvaccinated or whole-cell pertussis-vaccinated children. We conducted a population-based study of pertussis infection and reinfection during a 5-year period in California in an cohort vaccinated exclusively with acellular pertussis (aP) vaccine. METHODS: California surveillance data were reviewed to identify all children with 2 reported incidents of pertussis with symptom onset between 1 January 2010 and 31 December 2015. Case investigation reports were reviewed, and children with ≥2 episodes of symptomatic pertussis infection that met the case definition were included. RESULTS: Of 26259 pertussis cases reported in children (aged <18 years), 27 children met the inclusion criteria. Recurrent cases occurred among children of all ages; 5 (19%) were <6 months of age at the time of their first illness. The time from initial infection to reinfection was <1 year in 11 (41%) cases. Twenty-one children (78%) had received ≥3 doses of diphtheria and tetanus toxoids and aP vaccine at the time of their first pertussis infection, 1 (4%) had received 1 dose, and 5 (19%) were unvaccinated. CONCLUSIONS: Recurrent cases of pertussis infection are extremely rare. Based on this surveillance data, approximately 0.1% of children who were infected with pertussis experienced a clinically significant second episode of pertussis within 4 years. More research is needed to understand the immune response to B. pertussis infection in children vaccinated with aP vaccines.

Subacute Sclerosing Panencephalitis: The Devastating Measles Complication That Might Be More Common Than Previously Estimated.

BACKGROUND: Subacute sclerosing panencephalitis (SSPE) is a fatal complication of measles. We reviewed California cases from 1998-2015 to understand risk factors for SPPE and estimate incidence. METHODS: SSPE cases had clinically compatible symptoms and measles antibody detection in cerebrospinal fluid (CSF) or medical record documentation of SSPE. Cases were identified though a state death certificate search, Centers for Disease Control and Prevention reports, or investigations for undiagnosed neurologic disease. Measles detection in CSF was performed by serology at the California Department of Public Health or at clinical laboratories. RESULTS: Seventeen SSPE cases were identified. Males outnumbered females 2.4:1. Twelve (71%) cases had a history of measles-like illness; all 12 had illness prior to 15 months of age. Eight (67%) children were exposed to measles in California. SSPE was diagnosed at a median age of 12 years (3-35 years), with a latency period of 9.5 years (2.5-34 years). Among measles cases reported to CDPH during 1988-1991, the incidence of SSPE was 1:1367 for children <5 years, and 1:609 for children <12 months at time of measles disease. CONCLUSIONS: SSPE cases in California occurred at a high rate among unvaccinated children, particularly those infected during infancy. Protection of unvaccinated infants requires avoidance of travel to endemic areas, or early vaccination prior to travel at age 6-11 months. Clinicians should be aware of SSPE in patients with compatible symptoms, even in older patients with no specific history of measles infection. SSPE demonstrates the high human cost of "natural" measles immunity.

Increased Risk for Meningococcal Disease Among Men Who Have Sex With Men in the United States, 2012-2015.

BACKGROUND: Several clusters of serogroup C meningococcal disease among men who have sex with men (MSM) have been reported in the United States in recent years. The epidemiology and risk of meningococcal disease among MSM is not well described. METHODS: All meningococcal disease cases among men aged 18-64 years reported to the National Notifiable Disease Surveillance System between January 2012 and June 2015 were reviewed. Characteristics of meningococcal disease cases among MSM and men not known to be MSM (non-MSM) were described. Annualized incidence rates among MSM and non-MSM were compared through calculation of the relative risk and 95% confidence intervals. Isolates from meningococcal disease cases among MSM were characterized using standard microbiological methods and whole-genome sequencing. RESULTS: Seventy-four cases of meningococcal disease were reported among MSM and 453 among non-MSM. Annualized incidence of meningococcal disease among MSM was 0.56 cases per 100000 population, compared to 0.14 among non-MSM, for a relative risk of 4.0 (95% confidence interval [CI], 3.1-5.1). Among the 64 MSM with known status, 38 (59%) were infected with human immunodeficiency virus (HIV). HIV-infected MSM had 10.1 times (95% CI, 6.1-16.6) the risk of HIV-uninfected MSM. All isolates from cluster-associated cases were serogroup C sequence type 11. CONCLUSIONS: MSM are at increased risk for meningococcal disease, although the incidence of disease remains low. HIV infection may be an important factor for this increased risk. Routine vaccination of HIV-infected persons with a quadrivalent meningococcal conjugate vaccine in accordance with Advisory Committee on Immunization Practices recommendations should be encouraged.

Advisory Committee on Immunization Practices Recommended Immunization Schedule for Adults Aged 19 Years or Older - United States, 2017.

In October 2016, the Advisory Committee on Immunization Practices (ACIP) voted to approve the Recommended Adult Immunization Schedule for Adults Aged 19 Years or Older-United States, 2017. The 2017 adult immunization schedule summarizes ACIP recommendations in two figures, footnotes for the figures, and a table of contraindications and precautions for vaccines recommended for adults. These documents are available at https://www.cdc.gov/vaccines/schedules. The full ACIP recommendations for each vaccine can be found at https://www.cdc.gov/vaccines/hcp/acip-recs/index.html. The 2017 adult immunization schedule was also reviewed and approved by the American College of Physicians (https://www.acponline.org), the American Academy of Family Physicians (https://www.aafp.org), the American College of Obstetricians and Gynecologists (http://www.acog.org), and the American College of Nurse-Midwives (http://www.midwife.org).

Advisory Committee on Immunization Practices Recommended Immunization Schedule for Adults Aged 19 Years or Older--United States, 2016.

In October 2015, the Advisory Committee on Immunization Practices (ACIP)* approved the Recommended Immunization Schedule for Adults Aged 19 Years or Older, United States, 2016. This schedule provides a summary of ACIP recommendations for the use of vaccines routinely recommended for adults aged 19 years or older in two figures, footnotes for each vaccine, and a table that describes primary contraindications and precautions for commonly used vaccines for adults. Although the figures in the adult immunization schedule illustrate recommended vaccinations that begin at age 19 years, the footnotes contain information on vaccines that are recommended for adults that may begin at age younger than age 19 years. The footnotes also contain vaccine dosing, intervals between doses, and other important information and should be read with the figures.

Notes from the Field: Outbreak of Serogroup B Meningococcal Disease at a University - California, 2016.

On January 31, 2016, the Santa Clara County Public Health Department (SCCPHD) was notified of a suspected case of meningococcal disease in a university undergraduate student. By February 2, two additional suspected cases had been reported in undergraduate students living on the same campus. The index patient (patient A) required intensive care, whereas patients B and C had milder illness; there were no deaths. All three patients were part of overlapping social networks and had attended the same events during the week before the onset of patient A's symptoms, but whether they had direct contact with one another could not be verified. Serogroup B Neisseria meningitidis was identified in cerebrospinal fluid and blood from patient A and in blood from patient B. Serogroup B has been responsible for all U.S. college outbreaks of meningococcal disease since 2011 (1). Laboratory results for patient C were inconclusive.

Outbreak of Serogroup C Meningococcal Disease Primarily Affecting Men Who Have Sex with Men - Southern California, 2016.

During March 4-August 11, 2016, 25 outbreak-associated cases of meningococcal disease, including two deaths (8% case-fatality ratio), were reported in Southern California. Twenty-four of the cases were caused by serogroup C Neisseria meningitidis (NmC) and one by N. meningitidis with an undetermined serogroup (Figure). On June 24, 2016, in response to this increase in NmC cases, primarily among men who have sex with men (MSM) in Los Angeles County, the city of Long Beach, and Orange County, the California Department of Public Health (CDPH) issued a press release and health advisory, declaring an outbreak of NmC in Southern California (1).

Risk Factors Associated With Infant Deaths From Pertussis: A Case-Control Study.

BACKGROUND: In the current era, most pertussis deaths occur in infants <3 months of age. Leukocytosis with lymphocytosis and pneumonia are commonly observed among cases of severe pertussis. METHODS: Risk factors associated with fatal pertussis were identified by comparing fatal pertussis cases among patients <120 days of age occurring from 1 January 1998 through 26 December 2014, matched by age (<120 days), county of residence, and closest symptom onset date with 1-4 nonfatal hospitalized cases. California Department of Public Health surveillance data were reviewed to identify cases; demographics, clinical presentation, and course were abstracted from corresponding birth and medical records. Logistic regression and classification tree analyses were used to examine the risk of fatal pertussis with respect to identified factors. RESULTS: Fifty-three fatal infant pertussis cases were identified and compared with 183 nonfatal hospitalized pertussis cases. Fatal cases had significantly lower birth weight, younger gestational age, younger age at time of cough onset, and higher peak white blood cell (WBC) and lymphocyte counts. Fatal cases were less likely to have received macrolide antibiotics and more likely to have received steroids or nitric oxide and to develop pulmonary hypertension, seizures, encephalitis, and pneumonia. Additionally, exchange transfusion, extracorporeal membrane oxygenation, and intubation occurred significantly more frequently among fatal cases. In multivariate analyses, peak WBC count, birth weight, intubation, and receipt of nitric oxide were predictors of death. CONCLUSIONS: Early recognition of pertussis in young infants and treatment with appropriate antibiotic therapy are important in preventing death. Several risk factors are strongly associated with fatal pertussis in infants.

Advisory committee on immunization practices recommended immunization schedule for adults aged 19 years or older--United States, 2015.

In October 2014, the Advisory Committee on Immunization Practices (ACIP) approved the Recommended Immunization Schedule for Adults Aged 19 Years or Older, United States, 2015. This schedule provides a summary of ACIP recommendations for the use of vaccines routinely recommended for adults aged 19 years or older in two figures, footnotes for each vaccine, and a table that describes primary contraindications and precautions for commonly used vaccines for adults. Changes in the 2015 adult immunization schedule from the 2014 schedule included the August 2014 recommendation for routine administration of the 13-valent pneumococcal conjugate vaccine (PCV13) in series with the 23-valent pneumococcal polysaccharide vaccine (PPSV23) for all adults aged 65 years or older, the August 2014 revision on contraindications and precautions for the live attenuated influenza vaccine (LAIV), and the October 2014 approval by the Food and Drug Administration to expand the approved age for use of recombinant influenza vaccine (RIV). These revisions were also reviewed and approved by the American College of Physicians, American Academy of Family Physicians, American College of Obstetricians and Gynecologists, and American College of Nurse-Midwives.

Missed opportunities for tetanus postexposure prophylaxis--California, January 2008-March 2014.

Tetanus is an acute and sometimes fatal disease characterized by sudden muscle contractions. The number of tetanus cases reported annually in the United States has declined significantly since the 1930s and 1940s as a result of the introduction of tetanus vaccines. However, sporadic cases continue to occur in persons who are not up-to-date with tetanus toxoid-containing vaccinations (TT) and do not receive appropriate postexposure prophylaxis (PEP). To assess the extent of these cases, the California Department of Public Health reviewed all tetanus cases reported during January 2008-March 2014. A total of 21 tetanus patients were reported; five (24%) died. An average of three cases were reported each year during 2008-2013; the average annual incidence among patients aged ≥65 years (0.23 cases per 1 million population) was twice that among patients aged 21-64 years (0.10 cases per 1 million population). Of 16 patients with an acute injury before illness and diagnosis, nine (56%) sought medical care, and two (22%) of the nine received appropriate PEP. Although tetanus is rare, it is a life-threatening disease that is preventable. Health care providers should ensure that their patients are up-to-date with TT vaccination and provide appropriate postexposure prophylaxis for patients with wounds.

Measles outbreak--California, December 2014-February 2015.

On January 5, 2015, the California Department of Public Health (CDPH) was notified about a suspected measles case. The patient was a hospitalized, unvaccinated child, aged 11 years with rash onset on December 28. The only notable travel history during the exposure period was a visit to one of two adjacent Disney theme parks located in Orange County, California. On the same day, CDPH received reports of four additional suspected measles cases in California residents and two in Utah residents, all of whom reported visiting one or both Disney theme parks during December 17-20. By January 7,seven California measles cases had been confirmed, and CDPH issued a press release and an Epidemic Information Exchange (Epi-X) notification to other states regarding this outbreak. Measles transmission is ongoing.

Meningococcal disease among men who have sex with men - United States, January 2012-June 2015.

Since 2012, three clusters of serogroup C meningococcal disease among men who have sex with men (MSM) have been reported in the United States. During 2012, 13 cases of meningococcal disease among MSM were reported by the New York City Department of Health and Mental Hygiene (1); over a 5-month period during 2012­2013, the Los Angeles County Department of Public Health reported four cases among MSM; and during May­June 2015, the Chicago Department of Public Health reported seven cases of meningococcal disease among MSM in the greater Chicago area. MSM have not previously been considered at increased risk for meningococcal disease. Determining outbreak thresholds* for special populations of unknown size (such as MSM) can be difficult. The New York City health department declared an outbreak based on an estimated increased risk for meningococcal infection in 2012 among MSM and human immunodeficiency virus (HIV)­infected MSM compared with city residents who were not MSM or for whom MSM status was unknown (1). The Chicago Department of Public Health also declared an outbreak based on an increase in case counts and thresholds calculated using population estimates of MSM and HIV-infected MSM. Local public health response included increasing awareness among MSM, conducting contact tracing and providing chemoprophylaxis to close contacts, and offering vaccination to the population at risk (1­3). To better understand the epidemiology and burden of meningococcal disease in MSM populations in the United States and to inform recommendations, CDC analyzed data from a retrospective review of reported cases from January 2012 through June 2015.

The role of vaccination coverage, individual behaviors, and the public health response in the control of measles epidemics: an agent-based simulation for California.

BACKGROUND: Measles cases continue to occur among susceptible individuals despite the elimination of endemic measles transmission in the United States. Clustering of disease susceptibility can threaten herd immunity and impact the likelihood of disease outbreaks in a highly vaccinated population. Previous studies have examined the role of contact tracing to control infectious diseases among clustered populations, but have not explicitly modeled the public health response using an agent-based model. METHODS: We developed an agent-based simulation model of measles transmission using the Framework for Reconstructing Epidemiological Dynamics (FRED) and the Synthetic Population Database maintained by RTI International. The simulation of measles transmission was based on interactions among individuals in different places: households, schools, daycares, workplaces, and neighborhoods. The model simulated different levels of immunity clustering, vaccination coverage, and contact investigations with delays caused by individuals' behaviors and/or the delay in a health department's response. We examined the effects of these characteristics on the probability of uncontrolled measles outbreaks and the outbreak size in 365 days after the introduction of one index case into a synthetic population. RESULTS: We found that large measles outbreaks can be prevented with contact investigations and moderate contact rates by having (1) a very high vaccination coverage (≥ 95%) with a moderate to low level of immunity clustering (≤ 0.5) for individuals aged less than or equal to 18 years, or (2) a moderate vaccination coverage (85% or 90%) with no immunity clustering for individuals (≤ 18 years of age), a short intervention delay, and a high probability that a contact can be traced. Without contact investigations, measles outbreaks may be prevented by the highest vaccination coverage with no immunity clustering for individuals (≤ 18 years of age) with moderate contact rates; but for the highest contact rates, even the highest coverage with no immunity clustering for individuals (≤ 18 years of age) cannot completely prevent measles outbreaks. CONCLUSIONS: The simulation results demonstrated the importance of vaccination coverage, clustering of immunity, and contact investigations in preventing uncontrolled measles outbreaks.

Acute Flaccid Myelitis of Unknown Etiology in California, 2012-2015.

IMPORTANCE: There has been limited surveillance for acute flaccid paralysis in North America since the regional eradication of poliovirus. In 2012, the California Department of Public Health received several reports of acute flaccid paralysis cases of unknown etiology. OBJECTIVE: To quantify disease incidence and identify potential etiologies of acute flaccid paralysis cases with evidence of spinal motor neuron injury. DESIGN, SETTING, AND PARTICIPANTS: Case series of acute flaccid paralysis in patients with radiological or neurophysiological findings suggestive of spinal motor neuron involvement reported to the California Department of Public Health with symptom onset between June 2012 and July 2015. Patients meeting diagnostic criteria for other acute flaccid paralysis etiologies were excluded. Cerebrospinal fluid, serum samples, nasopharyngeal swab specimens, and stool specimens were submitted to the state laboratory for infectious agent testing. MAIN OUTCOMES AND MEASURES: Case incidence and infectious agent association. RESULTS: Fifty-nine cases were identified. Median age was 9 years (interquartile range [IQR], 4-14 years; 50 of the cases were younger than 21 years). Symptoms that preceded or were concurrent included respiratory or gastrointestinal illness (n = 54), fever (n = 47), and limb myalgia (n = 41). Fifty-six patients had T2 hyperintensity of spinal gray matter on magnetic resonance imaging and 43 patients had cerebrospinal fluid pleocytosis. During the course of the initial hospitalization, 42 patients received intravenous steroids; 43, intravenous immunoglobulin; and 13, plasma exchange; or a combination of these treatments. Among 45 patients with follow-up data, 38 had persistent weakness at a median follow-up of 9 months (IQR, 3-12 months). Two patients, both immunocompromised adults, died within 60 days of symptom onset. Enteroviruses were the most frequently detected pathogen in either nasopharynx swab specimens, stool specimens, serum samples (15 of 45 patients tested). No pathogens were isolated from the cerebrospinal fluid. The incidence of reported cases was significantly higher during a national enterovirus D68 outbreak occurring from August 2014 through January 2015 (0.16 cases per 100,000 person-years) compared with other monitoring periods (0.028 cases per 100,000 person-years; P <.001). CONCLUSIONS AND RELEVANCE: In this series of patients identified in California from June 2012 through July 2015, clinical manifestations indicated a rare but distinct syndrome of acute flaccid paralysis with evidence of spinal motor neuron involvement. The etiology remains undetermined, most patients were children and young adults, and motor weakness was prolonged.