2014-2015 Influenza Season, Boston Infectious Disease Bureau Boston Public Health Commission
Influenza Surveillance: Boston, 2014-2015 Influenza cases diagnosed in Boston and confirmed by any laboratory test must be reported to the city health department (Boston Public Health Commission, BPHC).
Influenza Surveillance: Boston, 2014-2015 BPHC syndromic surveillance data are used to track influenza-like illness (ILI) visits at acute care sites in Boston. During the season, data are used to inform control measures and provide community situational awareness. Data for this report were analyzed by BPHC after the influenza season.
Number of Reported Cases % ILI ED Visits Boston Public Health Commission Reported Influenza Cases* and Percent of Emergency Department Visits Due to Influenza-Like Illness (ILI)**, Boston, 2014-2015 400 350 300 250 200 150 100 50 0 Influenza Cases %ILI ED 4.0% 3.5% 3.0% 2.5% 2.0% 1.5% 1.0% 0.5% 0.0% -0.5% Week Ending Note: The 2014-2015 influenza season covers event dates between 11/1/2014-5/2/2015 *Reported cases: Boston Residents only. **ED ILI visits: All visits to Boston EDs regardless of residence
Number of Reported Cases Boston Public Health Commission Reported Influenza Cases* by Influenza Type, Boston Residents, 2014-2015 400 350 300 250 200 150 100 50 0 Influenza A Cases Influenza B Cases Week Ending *Reported cases: Boston Residents only.
% All Visits Due to ILI Boston Public Health Commission Percent Influenza-like Illness (ILI) of Boston Emergency Department Visits* 6% 5% 2012-2013 2013-2014 2014-2015 4% 3% 2% 1% 0% Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Note: The 2014-2015 influenza season covers event dates between 11/1/2014-5/2/2015 *All visits to Boston EDs regardless of residence
Characteristics of Reported Influenza Cases, Boston Residents, 2014-2015* Total Cases N=2327 Hospitalized 591 (25%) Died 38 (2%) Influenza A ** 1843 (80%) Influenza B ** 466 (20%) Male 1014 (44%) Female 1313 (56%) Pregnant (% of female cases) 26 (2%) Note: The 2014-2015 influenza season covers event dates between 11/1/2014-5/2/2015 **Eighteen cases had both influenza A and influenza B
Age Group (years) Boston Public Health Commission Reported Influenza Cases, Boston Residents*, 2014-2015 Age Age (years) and Gender 65+ 65+ yrs 28% 18-44 yrs 33% 45-64 18-44 Male 5-17 yrs 10% 45-64 yrs 22% 5-17 <5 Female <5 yrs 7% 600 400 200 0 200 400 600 Number of Cases *Boston Population, 2010 Census Data
Age Group (years) Boston Public Health Commission Reported Influenza Cases by Age in Boston Residents, Compared to the Boston Population*, 2014-2015 65+ 45-64 18-44 5-17 <5 0% 10% 20% 30% 40% 50% 60% Percent of Total Boston Population Reported Influenza Cases *Boston Population, 2010 Census Data
Reported Influenza Cases by Race/Ethnicity in Boston Residents, Compared to the Boston Population*, 2014-2015 White Black Latino Asian Other Unknown 0% 10% 20% 30% 40% 50% 60% Percent of Total Boston Population Reported Influenza Cases *Boston Population, 2010 Census Data
Characteristics of Hospitalized* Influenza Cases by Age, Boston Residents, 2014-2015 Age Group (years) <5 5-17 18-44 45-64 65+ All Ages % Cases Hospitalized 9% 11% 9% 25% 56% 25% Median LOS** (days) 3 2 2 3 4 3 Oseltamivir treatment 60% 82% 91% 91% 92% 90% Asthma 27% 55% 26% 31% 20% 24% Diabetes 0% 0% 15% 35% 42% 35% Pneumonia 20% 14% 36% 23% 37% 33% Presented with Fall*** 0% 0% 4% 12% 15% 12% *Data on length of stay, treatment, and co-morbidities missing for 15 cases (of 524 hospitalized) **LOS=length of stay *** Presented with Fall =cases who presented to a hospital as the direct result of a fall, but who were subsequently found to have laboratory-confirmed influenza
Characteristics of Hospitalized* Influenza Cases by Race, Boston Residents, 2014-2015 Reported Race White Black Latino Asian Total % Cases Hospitalized 30% 29% 25% 24% 25% Median LOS** (days) 4 3 3 2.5 3 Oseltamivir treatment 90% 89% 90% 92% 90% Asthma 16% 32% 37% 14% 24% Diabetes 30% 38% 44% 39% 35% Pneumonia 42% 25% 39% 25% 33% Presented With Fall*** 15% 10% 9% 17% 12% *Data on length of stay, treatment, and co-morbidities missing for 15 cases (of 524 hospitalized) **LOS=length of stay *** Presented with Fall =cases who presented to a hospital as the direct result of a fall, but who were subsequently found to have laboratory-confirmed influenza
Characteristics of Reported Influenza Cases* >64 Years of Age, by Age Range: Boston, 2014-2015 Gender Race Age Group (years) 65-84 85+ N=460 N=169 Male 43% 43% Female 57% 57% White 36% 56% Black 29% 19% Latino 14% 6% Asian 11% 6% Other 10% 13% Hospitalized 54% 62% Died 2% 12% *Reported cases: Boston Residents only.
Characteristics of Hospitalized Influenza Cases* >64 Years of Age, by Age Range: Boston, 2014-2015 Age Group (years) 65-84 85+ % Hospitalized 54% 62% Median LOS (days) 3 5 Oseltamivir treatment 93% 90% Asthma 24% 10% Diabetes 44% 38% Pneumonia 34% 45% Presented with Fall*** 11% 25% *Data on length of stay, treatment, and co-morbidities missing for 15 cases (of 524 hospitalized) **LOS=length of stay *** Presented with Fall =cases who presented to a hospital as the direct result of a fall, but who were subsequently found to have laboratory-confirmed influenza
Influenza A vs. Influenza B Cases by Race/Ethnicity and Age Group, Boston Residents, 2014-2015 Race/Ethnicity White Black Latino Asian Total Influenza A 82% 81% 78% 73% 80% Influenza B 18% 19% 22% 27% 20% Age Group (years) <5 5-17 18-44 45-64 65+ Total Influenza A 87% 76% 76% 81% 85% 80% Influenza B 13% 24% 24% 19% 15% 20%
Characteristics of Hospitalized* Influenza Cases by Influenza Type, Boston Residents, 2014-2015 Influenza A Influenza B % Cases Hospitalized 25% 25% Median LOS (days) 3 3 Oseltamivir treatment 90% 87% Asthma 24% 26% Diabetes 36% 21% Pneumonia 32% 39% Presented with Fall*** 15% 9% *Data on length of stay, treatment, and co-morbidities missing for 15 cases (of 524 hospitalized) **LOS=length of stay *** Presented with Fall =cases who presented to a hospital as the direct result of a fall, but who were subsequently found to have laboratory-confirmed influenza
Confirmed Influenza Cases and ILI ED Visits in Boston Residents, 2014-2015 Confirmed Influenza Cases, per 100,000 population,11/1/2014 5/2/2015 ILI Emergency Department Visits, per 100,000 population, 11/1/2014 5/2/2015 Neighborhood Legend A/B=Allston/Brighton BB=Back Bay CH=Charlestown EB=East Boston FW=Fenway HP=Hyde Park JP=Jamaica Plain MT=Mattapan ND=North Dorchester RS=Roslindale RX=Roxbury SB=South Boston SD=South Dorchester SE=South End WR=West Roxbury
Metro Boston FNY % ILI % ILI ED Visits* Boston Public Health Commission Comparison of ILI Using Flu Near You (FNY) and Boston Hospital Syndromic* Data, 2012-2015 % ILI ED Visits Metro Boston FNY % ILI 16 14 12 10 8 6 4 2 0 6 5 4 3 2 1 0 *All visits to Boston EDs regardless of residence MMWR Year and Week Flu Near You (FNY) compiles weekly data of ILI activity in the United States. The data come from short, weekly internet-based surveys completed by voluntary participants who indicate whether they are healthy or have experienced any of a short list of symptoms. The public may participate by enrolling in FNY at: https://flunearyou.org/
Influenza in Boston: 2014-2015 25% of reported cases were hospitalized. Despite current guidelines, not all hospitalized influenza cases were treated with an antiviral medication.
Influenza in Boston: 2014-2015 12% of hospitalized influenza cases sought healthcare due to a fall, not influenza. The elderly were more likely to present due to a fall. Information from a community participatory disease surveillance system correlated well with data from case reporting and syndromic surveillance.
Infectious Disease Bureau P: (617) 534-5611 F: (617) 534-5905 www.bphc.org/cdc