By NH POLITICIAN
Bureau of Infectious Disease Control Infectious Disease Surveillance Section (IDSS). Weekly Influenza Surveillance Report Week Ending March 21, 2020 MMWR Week 12.
The NH Department of Health and Human Services (DHHS) provides weekly influenza surveillance reports during the traditional influenza season, which starts at the beginning of October and continues through mid-May. The 2019–20 influenza season began on 9/29/2019.
Summary for New Hampshire
Influenza-Like Illness (ILI)
Acute Respiratory Illness (ARI)
Pneumonia and InfluenzaLike Illness (ILI) Related Deaths
Respiratory Specimens Submitted to the Laboratory
Flu Activity
Week 12
1.4% = decrease from previous week
5.4% = decrease from previous week
8.2% (below threshold*)
7 Specimens Submitted 2 positive for A(H1N1)pdm09 2 positive for B/Victoria lineage 3 negative
Widespread
*Epidemic threshold = 10.8%
New Hampshire Surveillance Outpatient Illness Surveillance The two components of outpatient illness surveillance in New Hampshire are as follows: 1. U.S. Outpatient Influenza-like Illness Surveillance Network (ILINet): Beginning in 1997, NH has participated in this collaborative effort between the Centers for Disease Control and Prevention, state and local health departments, and health care providers. For the 2019-20 influenza season, 17 NH health care providers are participating. Participating providers report the proportion of patients who present with influenza-like illness (ILI) on a weekly basis. ILI is defined as 1) a fever and 2) cough and/or sore throat, in the absence of a known cause. Participating providers are also asked to collect respiratory specimens from select patients and submit them to the PHL for viral subtyping. 2. The Automated Hospital Emergency Department Data (AHEDD) system: This system is a collaborative effort between NH acute care hospitals and the NH DHHS. Currently, 25 hospitals electronically transmit real-time data from emergency department encounters throughout the day to NH DHHS. However, data could only be used in a meaningful way for 19 of the reporting hospitals due to key changes in how some hospitals report chief complaint text into AHEDD (i.e., changes in method of reporting resulted in challenges at comparing to historical data for determining if respiratory illness was elevated). Chief complaint text within the system is queried for complaints of acute respiratory illness (ARI) in patients seen in emergency departments. While ARI includes encounters that fit the definition of ILI above, it also includes encounters for complaints such as acute bronchitis or otitis media.
NH Department of Health and Human Services MMWR 12 Division of Public Health Services Week Ending March 21, 2020 Bureau of Infectious Disease Control -2- Weekly Influenza Surveillance Report
Because these two systems collect information using different methods and represent different patient populations, it is expected that the proportions of ILI and ARI seen in these systems will differ. However, the overall trend of activity is expected to be similar.
Patient Visits/Encounters
Reporting Providers/Hospitals
ILI ARI
Change from Previous Week ILINet 18/1,279 9 1.4% Decrease from 3.1% AHEDD 418/7,730 19 5.4% Decrease from 5.6%
Maps illustrating the degree of ARI activity for each of the ten counties for weeks 12 and 13 are available at http://www.dhhs.nh.gov/dphs/cdcs/influenza/arisurveillance.htm
Laboratory Surveillance The NH Public Health Laboratories (PHL) receives respiratory specimens for influenza testing from health care providers and hospitals throughout the State. Testing is important to identify circulating influenza viral subtypes and to confirm specimens that test positive by rapid test.
Results of Specimens Received by the PHL and Cumulative Totals for the 2019-20 Influenza Season Week 12 (3/15/20–3/21/20) YTD (9/29/19–3/28/20) Results # specimens % of total positive # specimens % of total positive Influenza A (H3) 0 0 15 8.6 Influenza A (H1N1)pdm09 2 50.0 84 48.0 Influenza B/Victoria 2 50.0 75 42.9 Influenza B/Yamagata 0 0 1 0.6 Negative for influenza 3 133* Total 7 309** * Of specimens that tested negative for influenza, 1 was positive for adenovirus, 3 for Human Rhino / Enterovirus, 2 for Respiratory Syncytial Virus (RSV), 3 for Coronavirus HKU1, 2 for Human Metapneumovirus, and 1 for Parainfluenza_4. **One specimen result was reported as inconclusive.
NH Department of Health and Human Services MMWR 12 Division of Public Health Services Week Ending March 21, 2020 Bureau of Infectious Disease Control -3- Weekly Influenza Surveillance Report
Supplemental Influenza Results
In addition to PHL influenza test results, DHHS is now reporting supplemental influenza test results from participating clinical laboratories throughout the state. Supplemental influenza test results are for specimens collected from patients who present with respiratory illness and may be generated by a variety of assays, including real-time polymerase chain reaction (RT-PCR) or rapid influenza diagnostic tests (RIDT). Currently there are 14 clinical laboratories that report weekly test results. Results were reported for 701 specimens tested during week 12, and 65 (9.3%) were positive for influenza, which is a decrease compared to the previous week (19.4%).
Results of Specimens Tested by Supplemental Clinical Laboratories and Cumulative Totals for the 2019-20 Influenza Season
Week 12 (3/15/20–3/21/20) YTD (9/29/19–3/28/20)
RIDT PCR-based RIDT PCR-based
specimens
% of total positive Influenza A 19 70.4 22 57.9 470 48.0 1,808 49.7 Influenza B 8 29.6 16 42.1 509 52.0 1,831 50.3 Negative 241 395 4,753 11,131 Total 268 433 5,732 14,770
Pneumonia and Influenza (P&I) Mortality Pneumonia and Influenza (P&I) deaths in New Hampshire are identified through review of electronically filed death certificates by looking at the causes of death listed on each death certificate. The following graph, which shows the proportion of deaths attributed to P&I, represents all deaths recorded by NH’s
*Seasonal baseline is calculated using the previous 5 years of data. If the proportion of P&I deaths for a given week exceeds the baseline value for that week by a statistically significant amount (1.645 standard deviations), then P&I deaths are said to be above the epidemic threshold, and the proportion of deaths above threshold are considered attributable to influenza.
NH Department of Health and Human Services MMWR 12 Division of Public Health Services Week Ending March 21, 2020 Bureau of Infectious Disease Control -4- Weekly Influenza Surveillance Report
Division of Vital Records Administration. This includes resident and non-resident deaths that occurred within the State, and may not include deaths of NH residents that occurred out-of-state, or cases being investigated by the Medical Examiner’s Office. 8.2% of all deaths recorded in NH were reported as due to P&I. This is below the epidemic threshold of 10.8%. Twenty-nine adult influenza-related deaths have been identified so far this influenza season. The counties of residence for the persons with an identified influenza-related death are Carroll, Cheshire, Coos, Hillsborough, Merrimack, Rockingham, Strafford, and Sullivan. No pediatric influenza-related deaths have been identified this influenza season. Due to delays in electronic filing of death certificates, newly identified deaths in the last week may have occurred at any point during the flu season and not necessarily within the last week. School Surveillance for Absenteeism Beginning with the 2009-2010 school year, an influenza-like illness (ILI) web-reporting tool for NH schools was implemented to better evaluate trends of ILI in communities over time. All public schools were asked to voluntarily report daily aggregate counts for student and staff absenteeism, those absent for ILI, total school nurse visits, and nurse visits for ILI. An analysis tool has been developed, and student absenteeism and student ILI rates, reported by SAU, are posted on the DHHS website each week at http://www.dhhs.nh.gov/dphs/cdcs/influenza/schoolsurveillance.htm. There is no student absenteeism data to report for week 12 since schools are closed due to the COVID19 situation.
Student Absenteeism Overall Rate
Number of Schools Reporting
Percentage of Schools Reporting
Previous Week’s Overall Rate Total Absenteeism – – – 5.9 Influenza-Like-Illness – – – 0.5
Influenza Activity in New Hampshire as Assessed by the State Epidemiologist Overall influenza activity in NH for week 12 was widespread. Influenza activity in NH for week 13 was widespread, and will be included in CDC’s update for week 13.
Reported flu activity level is based on ILI reported by the participating providers and AHEDD surveillance systems, reported outbreaks in facilities, and reports of laboratory confirmed influenza. Influenza activity levels are defined by CDC as follows: No Activity: Low ILI activity and no laboratory-confirmed cases of influenza. Sporadic: Low ILI activity and isolated laboratory-confirmed influenza cases or a single influenza outbreak has been reported. Local: Increased ILI activity or influenza outbreaks in a single region of the state, and recent laboratory-confirmed influenza in that region. Regional: Increased ILI activity or influenza outbreaks in 2, but less than half of state regions, and recent laboratory-confirmed influenza in affected regions. Widespread: Increased ILI activity or influenza outbreaks in at least half of state regions, and recent laboratory-confirmed influenza in the state.
National Surveillance
National Geographic Spread of Influenza Widespread Regional Local Sporadic No Activity 38 states, including Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont Puerto Rico
10 states
2 states District of Columbia
0 states U.S. Virgin Islands 0 states
Laboratory confirmed flu activity as reported by clinical laboratories continues to decrease; however, influenza-like illness activity is increasing. Influenza severity indicators remain moderate to low overall, but hospitalization rates differ by age group, with high rates among children and young adults. Nationally, influenza A(H1N1)pdm09 viruses are now the most commonly reported influenza viruses this season. The proportion of outpatient visits for influenza-like illness (ILI) increased from 5.6% last week to 6.4% this week, and remained above the national baseline (2.4%). All of the 10 regions, including New England Region 1, remain above their respective baselines. The percentage of deaths attributed to pneumonia and influenza was 7.4%, above the epidemic threshold of 7.3%. Six influenza-associated pediatric deaths were reported to CDC during week 12. So far a total of 155 influenza-associated pediatric deaths have been reported to CDC for the 2019-2020 season. Of the 155 influenza-associated pediatric deaths, 99 were associated with influenza B and 56 were associated with influenza A.
Laboratory Surveillance Public Health laboratories located in all 50 states and Washington D.C. reported specimens testing positive during week 12 for influenza viruses, as follows:
Flu Season
Influenza A (H1N1) pdm09
Influenza A (H3N2)
Influenza A Unsubtyped
Influenza B – Yamagata lineage
Influenza B – Victoria lineage
Influenza B – lineage not performed
Percentage of Specimens Testing Positive
Week 12 2019-20
147 (67.1%)
13 (5.9%) 21 (9.6%) 0 (0.0%) 28 (12.8%) 10 (4.6%) 219/2,139 (10.2%)
NH Department of Health and Human Services MMWR 12 Division of Public Health Services Week Ending March 21, 2020 Bureau of Infectious Disease Control -6- Weekly Influenza Surveillance Report.
