H1N1 - Incidence/Presentation Resources

OBJECTIVE: To examine 2009 H1N1 influenza illness severity and the effect of antiviral treatment on the severity of illness among pregnant women. METHODS: We abstracted medical records from hospitalized pregnant (n=62) and nonpregnant (n=74) women with laboratory-confirmed 2009 H1N1 influenza in New York City, May through June 2009. We compared characteristics of pregnant and nonpregnant women and of severe and moderate influenza illness among pregnant women, with severe defined as illness resulting in intensive care admission or death. RESULTS: The 2009 H1N1 hospitalization rate was significantly higher among pregnant than nonpregnant women (55.3 compared with 7.7 per 100,000 population). Eight pregnant (including two deaths) and 16 nonpregnant (including four deaths) cases were severe. Pregnant women represented 6.4% of hospitalized cases and 4.3% of deaths caused by 2009 H1N1 influenza. Only 1 in 30 (3.3%) pregnant women who received oseltamivir treatment within 2 days of symptom onset had severe illness compared with 3 of 14 (21.4%) and four of nine (44.4%) pregnant women who started treatment 3–4 days and 5 days or more after symptom onset, respectively (P=.002 for trend). Severe and moderate 2009 H1N1 influenza illness occurred in all pregnancy trimesters, but most women (54.8%) were in the third trimester. Twenty-two women delivered during their influenza hospitalization, and severe neonatal outcomes (neonatal intensive care unit admission or death) occurred among five of six (83.3%) women with severe illness compared with 2 of 16 (12.5%) women with moderate illness (P=.004). CONCLUSION: Our findings highlight the potential for severe illness and adverse neonatal outcomes among pregnant 2009 H1N1 influenza-infected women and suggest the benefit of early oseltamivir treatment. (Obstet Gynecol 2010;115:717–26

BACKGROUND: During the spring of 2009, a pandemic influenza A (H1N1) virus emerged and spread globally. We describe the clinical characteristics of the patients who were hospitalized with 2009 H1N1 influenza in the United States from April 2009 to mid-June 2009.
METHODS: Using medical charts, we collected data on 272 patients who were hospitalized for at least 24 hours for influenza-like illness and who tested positive for the 2009 H1N1 virus with the use of a real-time reverse-transcriptase–polymerase-chain-reaction assay.
RESULTS: Of the 272 patients we studied, 25% were admitted to an intensive care unit and 7% died. Forty-five percent of the patients were children under the age of 18 years, and 5% were 65 years of age or older. Seventy-three percent of the patients had at least one underlying medical condition; these conditions included asthma; diabetes; heart, lung, and neurologic diseases; and pregnancy. Of the 249 patients who underwent chest radiography on admission, 100 (40%) had findings consistent with pneumonia. Of the 268 patients for whom data were available regarding the use of antiviral drugs, such therapy was initiated in 200 patients (75%) at a median of 3 days after the onset of illness. Data suggest that the use of antiviral drugs was beneficial in hospitalized patients, especially when such therapy was initiated early.
CONCLUSIONS: During the evaluation period, 2009 H1N1 influenza caused severe illness requiring hospitalization, including pneumonia and death. Nearly three quarters of the patients had one or more underlying medical conditions. Few severe illnesses were reported among persons 65 years of age or older. Patients seemed to benefit from antiviral therapy.

BACKGROUND: Pandemic H1N1 2009 influenza virus has been identified as the cause of a widespread outbreak of febrile respiratory infection in the USA and worldwide. We summarised cases of infection with pandemic H1N1 virus in pregnant women identified in the USA during the first month of the present outbreak, and deaths associated with this virus during the first 2 months of the outbreak.
METHODS: After initial reports of infection in pregnant women, the US Centers for Disease Control and Prevention (CDC) began systematically collecting additional information about cases and deaths in pregnant women in the USA with pandemic H1N1 virus infection as part of enhanced surveillance. A confirmed case was defined as an acute respiratory illness with laboratory-confirmed pandemic H1N1 virus infection by real-time reverse-transcriptase PCR or viral culture; a probable case was defined as a person with an acute febrile respiratory illness who was positive for influenza A, but negative for H1 and H3. We used population estimates derived from the 2007 census data to calculate rates of admission to hospital and illness.
FINDINGS: From April 15 to May 18, 2009, 34 confirmed or probable cases of pandemic H1N1 in pregnant women were reported to CDC from 13 states. 11 (32%) women were admitted to hospital. The estimated rate of admission for pandemic H1N1 influenza virus infection in pregnant women during the first month of the outbreak was higher than it was in the general population (0.32 per 100 000 pregnant women, 95% CI 0.13-0.52 vs 0.076 per 100 000 population at risk, 95% CI 0.07-0.09). Between April 15 and June 16, 2009, six deaths in pregnant women were reported to the CDC; all were in women who had developed pneumonia and subsequent acute respiratory distress syndrome requiring mechanical ventilation.
INTERPRETATION: Pregnant women might be at increased risk for complications from pandemic H1N1 virus infection. These data lend support to the present recommendation to promptly treat pregnant women with H1N1 influenza virus infection with anti-influenza drugs.

Background Like previous epidemic and pandemic diseases, 2009 pandemic influenza A (H1N1) may pose an increased risk of severe illness in pregnant women. Methods Statewide surveillance for patients who were hospitalized with or died from 2009 H1N1 influenza was initiated by the California Department of Public Health. We reviewed demographic and clinical data reported from April 23 through August 11, 2009, for all H1N1-infected, reproductive-age women who were hospitalized or died — nonpregnant women, pregnant women, and postpartum women (those who had delivered ≤2 weeks previously). Results Data were reported for 94 pregnant women, 8 postpartum women, and 137 nonpregnant women of reproductive age who were hospitalized with 2009 H1N1 influenza. Rapid antigen tests were falsely negative in 38% of the patients tested (58 of 153). Most pregnant patients (89 of 94 [95%]) were in the second or third trimester, and approximately one third (32 of 93 [34%]) had established risk factors for complications from influenza other than pregnancy. As compared with early antiviral treatment (administered ≤2 days after symptom onset) in pregnant women, later treatment was associated with admission to an intensive care unit (ICU) or death (relative risk, 4.3). In all, 18 pregnant women and 4 postpartum women (total, 22 of 102 [22%]) required intensive care, and 8 (8%) died. Six deliveries occurred in the ICU, including four emergency cesarean deliveries. The 2009 H1N1 influenza–specific maternal mortality ratio (the number of maternal deaths per 100,000 live births) was 4.3. Conclusions 2009 H1N1 influenza can cause severe illness and death in pregnant and postpartum women; regardless of the results of rapid antigen testing, prompt evaluation and antiviral treatment of influenza-like illness should be considered in such women. The high cause-specific maternal mortality rate suggests that 2009 H1N1 influenza may increase the 2009 maternal mortality ratio in the United States.

OBJECTIVE: The objective of the study was to characterize severe illness because of the 2009 pandemic influenza A (H1N1) infection in postpartum women. STUDY DESIGN: We reviewed case reports of infected hospitalized postpartum (
6 months from delivery) women identified through statewide surveillance in California. From April 23 through August 11, 2009, all hospitalizations and/or deaths were reported. After August 11, reporting was limited to cases requiring intensive care or deaths. RESULTS: From April 23 to December 31, 2009, 15 cases were reported; 11 (73%) had symptom onset within 7 days postpartum. Of 10 hospitalized cases reported through August 11, 4 required intensive care, 3 required mechanical ventilation, and 2 died. Of 5 cases requiring intensive care reported after August 11, all required mechanical ventilation and 1 died. Overall, 6 (43%) received antivirals within 48 hours of symptom onset. CONCLUSION: The 2009 H1N1 can cause severe illness in postpartum women, especially in the first week following delivery.

OBJECTIVE: The objective of the study was to characterize severe illness because of the 2009 pandemic influenza A (H1N1) infection in postpartum women. STUDY DESIGN: We reviewed case reports of infected hospitalized postpartum (6 months from delivery) women identified through statewide surveillance in California. From April 23 through August 11, 2009, all hospitalizations and/or deaths were reported. After August 11, reporting was limited to cases requiring intensive care or deaths. RESULTS: From April 23 to December 31, 2009, 15 cases were reported; 11 (73%) had symptom onset within 7 days postpartum. Of 10 hospitalized cases reported through August 11, 4 required intensive care, 3 required mechanical ventilation, and 2 died. Of 5 cases requiring intensive care reported after August 11, all required mechanical ventilation and 1 died. Overall, 6 (43%) received antivirals within 48 hours of symptom onset. CONCLUSION: The 2009 H1N1 can cause severe illness in postpartum women, especially in the first week following delivery.

An "In The Trenches" article (no formal abstract). Two cases of very severe maternal H1N1 illness are presented. This is followed by proposed guidelines for evaluation and treatment of H1N1 in pregnancy with extensive discussion in a Q&A format.

Comprehensive Website for California-specific information.
PREVENTION: Provides general information and access to posters and brochures.
VACCINATION: Information about the status of California's vaccine supply.
WHATS NEW: H1N1 (2009) Influenza Data and Statistics Update with reported hospitalized, ICU, and fatal cases of H1N1 (2009) influenza virus infections in California.
GUIDANCE: In the box section on the right, there is a section for California-specific guideline updates from CDPH.

Provides up to date links to a variety of good resources. Includes information for pregnant women and parents; information for clinicians and health officials, general H1N1 and seasonal flu information.

OVERVIEW: The single best place to visit for connections to a wide variety of resources (some of which we have individually indexed).
KEY STEP: Visit here often for updates.

Scroll down to see many useful charts and maps that can be easily swept into PPT presentations. Maps for prior weeks (for comparison) can be found at the very bottom of the page.

Clinician Outreach Communication Activity (COCA) Conference Calls are designed to serve as the venue for timely education and two-way communication with CDC Subject Matter Experts (SME).
FIND: Scroll to the September 29, 2009 date.
CONTENTS: Transcript and MP3 audio recording that go with the Slide Set (Slides are in the CMQCC H1N1 Documents area (below) or can be directly downloaded from this same site). The presentation is broken into 5 areas: Overview of influenza; Infection control guidance; Testing and treatment; Vaccination; and The Atlanta experience.

Slide set (55 slides) discussing the latest CDC guidelines with some background. Largely replaces the earlier CDC COCA slides.

A good general slide set made for OB Grand Rounds or Nursing Education. Covers epidemiology, pregnancy risks, triage assessment, treatment and prophylaxis, vaccine issues, and isolation/visitor policies.

Clinician Outreach Communication Activity (COCA) Conference Calls are designed to serve as the venue for timely education and two-way communication with CDC Subject Matter Experts (SME).
SLIDE SET: broken into 5 areas: Overview of influenza; Infection control guidance; Testing and treatment; Vaccination; and The Atlanta experience. Note that this slide set is in.pps format so that it is not editable.
TRANSCRIPT AND AUDIO TAPE: can be obtained using the citation noted in Web Resources with the same authors.