Influenza in the Pediatric Population

Amit Patel

Lock Haven University

Preceptor: Dr. Bhatt

What is influenza?

• We know it commonly as the “flu”• It is an acute febrile respiratory illness that

is highly contagious• Caused by RNA viruses of the

Orthomyxoviridae family (multiple types and subtypes)

• Although commonly confused with the common cold it is a much more severe disease

Types of influenza virus

• Composed of five types:• Influenzavirus A

• Most virulent and causes the most severe disease

• Known to have caused multiple epidemics and pandemics

• Influenzavirus B• Less common than Influenzavirus A and

causes less severe disease• Influenzavirus C• Isavirus• Thogotovirus

Eight segments of viral RNA are contained within the envelope and matrix (M1) shell. Each codes for one or two proteins that form the virus or regulate its intracellular replication.

• Roughly spherical virus (80-120 nm)

• Genome consists of eight segments of viral RNA

• Encodes for surface antigen proteins such as hemagglutinin (HA) and neuraminidase (NA)

• Lack RNA proof-reading enzymes hence errors/mutations are very common

Antigenic Drifts & Shifts

Signs/Symptoms

• Signs• Cervical

lymphadenopathy• Inflammation of

the mucous membranes

• Membranes reddened but no exudate

• Symptoms• Abrupt onset of

high fevers and chills

• Malaise• Myalgia • Headache with

photophobia• Nonproductive

cough• GI disturbance• Sneezing, sore

throat, nasal discharge

Epidemiology and Demographics• Influenza imposes a heavy disease burden on U.S.

society in an average year• Annual hospitalizations for influenza-associated

illness have been estimated at 334,000• In the U.S. annual incidence of influenza-related

deaths is approximately 20,000 deaths/year• Peak incidence is during the winter and usually lasts from

five to six weeks depending on locality• Influenza Viruses can cause disease among persons in

any age, but rates of infection are highest among children.

• Influenza immunization rates have an impact on both the direct medical costs and indirect costs associated with influenza• $1.7 billion dollars spent for medical costs in children

and additional $2.1 billion in indirect costs.

Spread of Influenza

• Influenza is spread from person to person primarily by droplets expelled by coughing or sneezing.

• It can also be spread by direct contact with influenza virus contaminated surfaces.

• Infected children easily spread disease to adults, other children within the family or to a community

• Community outbreaks last 4-8 weeks or longer

• Contagiousness starts from the day before symptoms begin and continues through 6th to 10th day of symptom onset.

Complications of Influenza

• Otitis media • Febrile seizures• Croup• Bronchiolitis or Pneumonia• Encephalopathy• Transverse myelitis • Myositis• Myocarditis • Pericarditis• Reye’s Syndrome

Influenza Vaccines• Inactivated Vaccine, Injectable (TIV)

• Fluzone (Sanofi-Pasteur), Fluvirin (Novartis), Flurix (GSK), FluLuval (GSK)

• Live-attenuated, Nasal (LAIV)• Flumist (MedImmune)

• Vaccine is traditionally recommended from the beginning of October through the end of January.

• To cover late outbreaks and more than one peak of influenza, vaccine is now recommended at least until the end of March/April.

• Both vaccines are cost-effective strategies for preventing influenza for both children and their families.

• Limited dates suggest that LAIV provides greater protection than TIV for young children.

Treatment

• Symptomatic• Antivirals may be used if onset of symptoms is <48

hours• Neuraminidase inhibitors

• Tamiflu (oseltamvir)• Influenza A H1N1 strain showing significant

resistance this season• Relenza (zanamivir)

• Effective against all strains this season• M2 inhibitors

• Amantadine and rimantadine both showing resistance

CDC Recommendations (2008)• All children, both healthy and with high-risk conditions,

between the ages of 6 months to 18 years.• All pregnant women (pregnant during influenza season),

regardless of their stage of pregnancy• Children and adolescents with chronic illness, such as

asthma, diabetes, kidney disease, immune suppression, hemoglobinopathies, and lung or heart disease

• Children and adolescents with cognitive dysfunction, seizure disorders, neuromuscular disorders or spinal cord injuries

• Children and adolescents receiving long-term aspirin therapy

• Family members or caregivers of young children and other children at risk

• Children and adolescents who are residents of nursing homes, and other chronic-care facilities

• Health care professionals

CDC Estimated Influenza Vaccine Coverage Rates for Pediatric Populations: 2006-2007

Age GroupVaccination

Level

6-23 months 13.9%-46.6%

24-59 months 6.2%-22.4%

5-17 years 33%

PICO Question

• In pediatric patients from 6 months to 18 years of age what is the impact of various office activities to increase influenza vaccination coverage on actual vaccine rates?

PIC (Pediatric influenza vaccine coverage) Study• Objectives

• To describe influenza vaccine coverage in children aged <18 years in practicing pediatricians’ offices

• To examine correlations between in-office influenza vaccine coverage and the use of various tactics to increase vaccine coverage

• Study Design• A prospective, observational study conducted during

the 2007-2008 influenza season• Geographically balanced sample of 44 US outpatient

pediatric practices• Study endpoints

• Influenza vaccination coverage in children aged <18 years by age group

• Compliance with the recommended 2-dose regimen in unvaccinated children

• Correlation of office vaccination–related attitudes and activities with actual vaccine coverage

PIC Study: Demographics of Outpatient Pediatric Practices

Practice Characteristics Mean (range)

Practice size (n=44)

Practicing physicians per site 3 (1-9)

Nurses per site 4 (0-18)

Other staff per site 6 (0-42)

Pediatric patients in practice 9780 (630-37,312)

6-23 months 1827 (40-16,200)

24-59 months 1925 (168-9136)

5-8 years 1829 (150-9022)

9-17 years 3032 (120-17,500)

Influenza Vaccination Coverage Rates

• The mean vaccination rate was 18% for children aged 6 months to 17 years receiving ≥1 dose of influenza vaccine

Age Group

Immunization Rates, % (Range)

6-23 months

37 (1-90)

24-59 months

24 (2-75)

5-8 years

19 (1-44)

9-17 years

12 (1-60)

Compliance With 2-dose Regimen

• Compliance was lower among children eligible for the VFC program

• Disparity was largest among older children

• Compliance with the recommended 2-dose regimen was similar to CDC estimates from previous seasons

59.2

51

30.9

44.9

33.6

17.7

0

10

20

30

40

50

60

70

6-23 months 24-59months

5-8 years

Age Group

Com

plia

nce

Rate

(%

)

Non-VFC VFC

When Did Sites Offer Influenza Vaccine?

0

10

20

30

40

50

60

70

80

90

100

8/1 9/1 10/1 11/1 12/1 1/1 2/1 3/1 4/1 5/1

2007 2008

Activities Practiced by Sites to Increase Influenza Vaccination Rates

0 20 40 60 80 100

Resopndents (%)

Influenza vaccination during normal hours

Verbal recommendation during office visits

Posters in office/waiting area

Flyers/reading material available in office/waiting area

Handing out reading material during office visits

Telephone reminders to patients

Activities Practiced by Sites to Increase Vaccination Coverage and Compliance

Activities Correlated With Increased Vaccination Rates`

Increased Vaccination CoverageIncreased Compliance With

2-dose Regimen

6-59 months 5-17 years 6 months-8 years

More normal working hours during which influenza vaccination was offered P<0.0001 P=0.043

Fewer children eligible for VFC P<0.060 P<0.0001

Local mobile vaccine P<0.012

More patients receiving intranasal vaccine P<0.087

More months of offering influenza vaccine during normal work hours

P<0.0004 P<0.0001

Fewer months of phone call reminders to patients P=0.002

More nurses on staff P=0.096

Fewer “other” non-physician, non-nurse staff P=0.0003

Having a standing order for influenza vaccine administration P<0.0001

Local media coverage P<0.0001

Fewer months of educational workshops for clinic staff P<0.0002

Longer duration of vaccine availability in the previous season P<0.003

Fewer months of distributed education reading material P<0.006

More children receiving injectable vaccine in prefilled syringes P<0.007

Local school vaccine programs P<0.057

Conclusions

• Vaccination coverage and compliance with the 2-dose regimen varied significantly across sites and decreased as patient age increased• Compliance with the 2-dose regimen was lower

among children eligible for the VFC program, and the disparity was greatest in older children

• Offering vaccination during more normal working hours, having more months of vaccine availability, and standing orders were correlated with increased delivery of influenza vaccinations

• No specific reminder methods were prominent predictors of increased vaccination

Conclusions cont’d

• To implement the new ACIP recommendation to vaccinate all children aged 6 months to 18 years against influenza each year, additional resources will be needed, particularly for outreach to older children and those included in the VFC program

• It is hoped that broader routine influenza immunization will reduce the financial cost attributable to influenza among people of all ages while improving the health of all children and families.

So what does all of this mean?

• Those who are working in primary care need to make a push to vaccinate according to ACIP/CDC guidelines

• It is still unclear if the financial benefits will pan out since at least an additional 30 million more need to be vaccinated according to recommendations.

• Will the pharmaceutical companies be able to meet the demand?

References• Roskos, Steven E. (Aug 2007).Vaccines for preventing influenza in

healthy children. American Family Physician. 74(7), 1123-5. • Langley, Joanne M. , & Faughnan, Marie E. (Nov 2004). Prevention of

influenza in the general population. Canadian Medical Association Journal. 171, 1213-22.

• Rothberg, Michael B. , Haessler, Sarah D. , & Brown, Richard B. (April 2008). Complications of Viral Influenza. The American Journal of Medicine. 121(4), 258-64.

• Ebell, Mark H. (Nov 2005).Diagnosing and Treating Patients with Suspected Influenza. American Family Physician. 72(9), 1789-92.

• Eccles, Ron (Nov 2005).Understanding the symptoms of the common cold and influenza . The Lancet Infectious Diseases. 5(11), 718-25.

• Fiore AE, Shay DK, Broder K, et al. Prevention and control of influenza: recommendations of the Advisory Committee on Immunization Practices (ACIP), 2008. MMWR Recomm Rep 2008; 57(RR-7): 1-60.

• Centers for Disease Control and Prevention. Influenza vaccination coverage among children aged 6-23 months--United States, 2005-06 influenza season. MMWR Morb Mortal Wkly Rep 2007; 56(37): 959-63.

• Jackson LA, Neuzil KM, Baggs J, et al. Compliance with the recommendations for 2 doses of trivalent inactivated influenza vaccine in children less than 9 years of age receiving influenza vaccine for the first time: a Vaccine Safety Datalink study. Pediatrics 2006; 118(5): 2032-7.

• Briss PA, Rodewald LE, Hinman AR, et al. Reviews of evidence regarding interventions to improve vaccination coverage in children, adolescents, and adults. The Task Force on Community Preventive Services. Am J Prev Med 2000; 18(1 Suppl): 97-140.

Questions?