Jacqueline Gindler

Epidemiology of 2009 Pandemic Influenza A (H1N1) in the United States

In April 2009, the Centers for Disease Control and Prevention confirmed 2 cases of 2009 pandemic influenza A (H1N1) virus infection in children from southern California, marking the beginning of what would be the first influenza pandemic of the twenty-first century. This report describes the epidemiology of the 2009 H1N1 pandemic in the United States, including characterization of cases, fluctuations of disease burden over the course of a year, the age distribution of illness and severe outcomes, and estimation of the overall burden of disease.

Folic acid supplements during pregnancy and risk of miscarriage

BACKGROUND Although taking supplements that contain 400 microg of folic acid before and during early pregnancy reduces a womans risk for having a baby with a neural-tube defect (NTD), the effects of such supplements on other pregnancy outcomes remain unclear. We examined whether the use of such supplements affects the occurrence of miscarriage. METHODS Participants were women in China who had taken part in a recent folic acid campaign to prevent NTDs and who had registered in this campaign before they became pregnant for the first time. We examined the risk for miscarriage among women who had confirmed pregnancies and who had or had not taken pills containing only 400 microg of folic acid before and during early pregnancy. RESULTS The overall rate of miscarriage was 9.1% (2155/23806). The rates of miscarriage among women who had and had not taken folic acid pills before and during the first trimester were 9.0% and 9.3%, respectively (risk ratio 0.97 [95% CI 0.84-1.12]). The distributions of gestational age at pregnancy diagnosis and at miscarriage were similar for both groups of women. INTERPRETATION In this population-based study of a cohort of women whose use of folic acid supplements while pregnant had been previously documented and who had been pregnant for the first time, we found no evidence that daily consumption of 400 microg of folic acid before and during early pregnancy influenced their risk for miscarriage.

MTHFR 677C→T genotype is associated with folate and homocysteine concentrations in a large, population-based, double-blind trial of folic acid supplementation

BACKGROUND The methylenetetrahydrofolate reductase (MTHFR) genotype is associated with modification of disease and risk of neural tube defects. Plasma and red blood cell (RBC) folate and plasma homocysteine concentrations change in response to daily intakes of folic acid supplements, but no large-scale or population-based randomized trials have examined whether the MTHFR genotype modifies the observed response. OBJECTIVE We sought to determine whether the MTHFR 677C→T genotype modifies the response to folic acid supplementation during and 3 mo after discontinuation of supplementation. DESIGN Northern Chinese women of childbearing age were enrolled in a 6-mo supplementation trial of different folic acid doses: 100, 400, and 4000 μg/d and 4000 μg/wk. Plasma and RBC folate and plasma homocysteine concentrations were measured at baseline; after 1, 3, and 6 mo of supplementation; and 3 mo after discontinuation of supplementation. MTHFR genotyping was performed to identify a C→T mutation at position 677 (n = 932). RESULTS Plasma and RBC folate and homocysteine concentrations were associated with MTHFR genotype throughout the supplementation trial, regardless of folic acid dose. MTHFR TT was associated with lower folate concentrations, and the trend of TT < CC was maintained at even the highest doses. Folic acid doses of 100 μg/d or 4000 μg/wk did not reduce high homocysteine concentrations in those with the MTHFR TT genotype. CONCLUSION MTHFR genotype was an independent predictor of plasma and RBC folate and plasma homocysteine concentrations and did not have a significant interaction with folic acid dose during supplementation. This trial was registered at clinicaltrials.gov as NCT00207558.

Hospitalized Patients with 2009 Pandemic Influenza A (H1N1) Virus Infection in the United States—September–October 2009

Given the potential worsening clinical severity of 2009 pandemic influenza A (H1N1) virus (pH1N1) infection from spring to fall 2009, we conducted a clinical case series among patients hospitalized with pH1N1 infection from September through October 2009. A case patient was defined as a hospitalized person who had test results positive for pH1N1 virus by real-time reverse-transcription polymerase chain reaction. Among 255 hospitalized patients, 34% were admitted to an intensive care unit and 8% died. Thirty-four percent of patients were children <18 years of age, 8% were adults ≥ 65 years of age, and 67% had an underlying medical condition. Chest radiographs obtained at hospital admission that had findings that were consistent with pneumonia were noted in 103 (46%) of 255 patients. Among 255 hospitalized patients, 208 (82%) received neuraminidase inhibitors, but only 47% had treatment started ≤ 2 days after illness onset. Overall, characteristics of hospitalized patients with pH1N1 infection in fall 2009 were similar to characteristics of patients hospitalized with pH1N1 infection in spring 2009, which suggests that clinical severity did not change substantially over this period.

Epidemiology of measles in the United States in 1989 and 1990

During 1989 and 1990 measles incidence increased sharply in the United States. We compared cases reported during these years with those reported between 1981 and 1988. Incidence increased 462% in 1989, and incidence in 1990 (11.2/100,000) was the highest in more than a decade. Although all ages were affected the greatest increases were in children < 5 years and in adults. Incidence was 7- to 10-fold higher among racial/ethnic minority preschoolers than whites, and 80% of vaccine-eligible preschool age cases were unvaccinated. Complications occurred in 9418 (20.5%) cases, most frequently in young children and adults. Large urban outbreaks affecting predominantly unvaccinated preschoolers were common; 47% of all cases reported in 1990 were associated with 5 outbreaks. Reasons for the increased incidence are not clear. Current information suggests no change in vaccination coverage among preschool age children or in vaccine efficacy. Continued surveillance and evaluation of epidemiologic and laboratory data are necessary. The most pressing need is to improve age-appropriate vaccination among preschool age children.

Folic acid supplements during early pregnancy and likelihood of multiple births: a population-based cohort study.

BACKGROUND Folic acid supplements are recommended for women of childbearing age to prevent neural tube defects in their offspring. Results of some studies, however, suggest an increase in multiple births associated with use of vitamin supplements that contain folic acid during pregnancy. Our aim was to assess this association. METHODS We used data from a population-based cohort study from which we assessed the occurrence of multiple births in women (n=242015) who had participated in a campaign to prevent neural tube defects with folic acid supplements (400 microg per day) in China. Folic acid use was ascertained before pregnancy outcome was known. We studied the relation between multiple births and any use of folic acid pills before or during early pregnancy; additionally, we investigated mechanisms by which folic acid could potentially affect the occurrence of multiple births by examining pill-taking at three time periods: before ovulation, around the time of fertilisation, and after conception. FINDINGS 1496 (0.62%) multiple births occurred in a cohort of 242015 women who had registered with the study between October, 1993, and September, 1995, and who had a pregnancy not affected by a birth defect; the rate of multiple births in women who did and did not take folic acid before or during early pregnancy was 0.59% and 0.65%, respectively (rate ratio 0.91; 95% CI 0.82-1.00). INTERPRETATION Our findings suggest that consumption of folic acid supplements during pregnancy is not associated with an increased occurrence of multiple births.

Epidemiology of 2009 Pandemic Influenza A (H1N1) Deaths in the United States, April–July 2009

During the spring of 2009, pandemic influenza A (H1N1) virus (pH1N1) was recognized and rapidly spread worldwide. To describe the geographic distribution and patient characteristics of pH1N1-associated deaths in the United States, the Centers for Disease Control and Prevention requested information from health departments on all laboratory-confirmed pH1N1 deaths reported from 17 April through 23 July 2009. Data were collected using medical charts, medical examiner reports, and death certificates. A total of 377 pH1N1-associated deaths were identified, for a mortality rate of .12 deaths per 100,000 population. Activity was geographically localized, with the highest mortality rates in Hawaii, New York, and Utah. Seventy-six percent of deaths occurred in persons aged 18-65 years, and 9% occurred in persons aged ≥ 65 years. Underlying medical conditions were reported for 78% of deaths: chronic lung disease among adults (39%) and neurologic disease among children (54%). Overall mortality associated with pH1N1 was low; however, the majority of deaths occurred in persons aged <65 years with underlying medical conditions.

Racial and Ethnic Disparities in Hospitalizations and Deaths Associated with 2009 Pandemic Influenza A (H1N1) Virus Infections in the United States

PURPOSE Concerns have been raised regarding possible racial-ethnic disparities in 2009 pandemic influenza A (H1N1) (pH1N1) illness severity and health consequences for U.S. minority populations. METHODS Using data from the Centers for Disease Control and Preventions Behavioral Risk Factor Surveillance System, Emerging Infections Program Influenza-Associated Hospitalization Surveillance, and Influenza-Associated Pediatric Mortality Surveillance, we calculated race-ethnicity-specific, age-adjusted rates of self-reported influenza-like illness (ILI) and pH1N1-associated hospitalizations. We used χ(2) tests to evaluate racial-ethnic disparities in ILI-associated health care-seeking behavior and pH1N1 hospitalization. To evaluate pediatric deaths, we compared racial-ethnic proportions of deaths against U.S. population distributions. RESULTS Prevalence of self-reported ILI was lower among Hispanics (6.5%), higher among American Indians/Alaska Natives (16.2%), and similar among non-Hispanic blacks (7.7%) compared with non-Hispanic whites (8.5%). No racial-ethnic differences were identified in ILI-associated health care-seeking behavior. Age-adjusted pH1N1-associated Emerging Infections Program hospitalization rates were higher among all minority populations (range: 8.1-10.9/100,000 population) compared with non-Hispanic whites (3.0/100,000). The proportion of pH1N1-associated pediatric deaths was higher than expected among Hispanics (31%) and lower than expected among non-Hispanic whites (45%) given the proportions of the U.S. population they comprise (22% and 58%, respectively). CONCLUSIONS Racial-ethnic disparities in pH1N1-associated hospitalizations and pediatric deaths were identified. Vaccination remains the primary intervention for preventing influenza.

Experiences with provider and parental attitudes and practices regarding the administration of multiple injections during infant vaccination visits: lessons for vaccine introduction.

INTRODUCTION An increasing proportion of childhood immunization visits include administration of multiple injections. Future introduction of vaccines to protect against multiple diseases will further increase the number of injections at routine immunization childhood visits, particularly in developing countries that are still scaling up introductions. Parental and healthcare provider attitudes toward multiple injections may affect acceptance of recommended vaccines, and understanding these attitudes may help to inform critical decisions about vaccine introduction. METHODS We conducted a systematic review of the literature to examine factors underlying reported parental and healthcare provider concerns and practices related to administration of multiple injections during childhood vaccination visits. RESULTS Forty-four articles were identified; 42 (95%) were from high income countries, including 27 (61%) from the USA. Providers and parents report concerns about multiple injections, which tend to increase with increasing numbers of injections. Common parental and provider concerns included apprehension about the pain experienced by the child, worry about potential side effects, and uncertainty about vaccine effectiveness. Multiple studies reported that a positive provider recommendation to the parent and a high level of concern about the severity of the target disease were significantly associated with parental acceptance of all injections. Providers often significantly overestimated parental concerns about multiple injections. DISCUSSION Providers may play a critical role in the decision for a child to receive all recommended injections. Their overestimation of parental concerns may lead them to postpone recommended vaccinations, which may result in extra visits and delayed vaccination. More research is needed on interventions to overcome provider and parental concern about multiple injections, particularly in developing countries.

Acute Measles Mortality in the United States, 1987–2002

We used capture-recapture methodology to estimate total deaths and efficiency of reporting for 2 systems. During 1987-1992, there were 165 measles-associated deaths in the multiple-cause mortality database at the National Center for Health Statistics (NCHS) and 184 reported to the measles surveillance system at the National Immunization Program (NIP). We estimated that 259 measles deaths actually occurred; the reporting efficiencies were 64% for the NCHS and 71% for the NIP. Overall the death-to-case ratio was 2.54 and 2.83 deaths/1000 reported cases, using the NCHS and NIP data, respectively. Pneumonia was a complication among 67% of measles-related deaths in the NCHS data and 86% of deaths in the NIP data. Encephalitis was reported in 11% of deaths in both databases. Preexisting conditions related to immune deficiency were reported for 16% of deaths in the NCHS system and 14% in the NIP; the most common was human immunodeficiency virus infection. Overall, 90% of deaths reported to the NIP occurred in persons who had not been vaccinated against measles. During 1993-1999, only 1 acute measles-related death was reported to the NCHS and no deaths were reported to the NIP. This is consistent with the extremely low reported incidence of measles in the United States during these years.