Influenza: Signs, Symptoms, Treatment, and Prevention Nursing CE Course

1.0 ANCC Contact Hours AACN Category A

Syllabus

Objectives

At the conclusion of this activity, the reader should expect to be able to:

  1. Review the background definitions and terms regarding influenza.
  2. Discuss the statistics regarding influenza rates, morbidity and mortality associated with influenza infection, and rates of vaccination.
  3. Validate the importance of prevention and describe ways that nurses are involved in influenza prevention.
  4. Recall the signs and symptoms of influenza infection.
  5. Examine the testing options for diagnosing influenza.
  6. Explain potential complications and appraise the treatment protocols for influenza infection.


Overview

            Influenza (“the flu”) is a viral upper respiratory infection that can infect the nose, throat, and sometimes the lungs. Disease can vary from mild to severe, depending on the strain of virus as well as the immunity and overall health of the patient infected (CDCb, 2018). The typical flu season in the United States (US) lasts from October to March, but the year of 2017 lasted until May (Hammond, et al., 2018). Discovered in the 1930’s, there are three different types of flu virus: A, B & C. Type A is more contagious and causes moderate to severe illness in humans, birds, and swine. The most predominant strain seen in 2017, H3N2, was a type A virus. Type B causes a milder disease, and is more commonly seen in children, college campuses and long-term care facilities. Type B viruses mutate or change more slowly than type A. Type C is the most benign, oftentimes going undetected altogether as the patient does not realize they are ill. Type B & C viruses only infect humans. Transmission is usually person-to-person via airborne droplet (Cannon, Bauer, Weust & Southard, 2018).

            According to the World Health Organization (WHO), during the 2017-18 flu season 68-71% of flu cases in the US were attributed to type A, and 29-32% to type B. Of those, about 85% of the subtyped influenza A viruses were H3N2. While there was reportedly good coverage from vaccinations, the morbidity and mortality of the 2017-18 season was higher than previous seasons. Hospitalization rates in the US were 106.6 per 100,000, with adults over the age of 65 accounting for about 58% of those. Vaccine effectiveness (VE) was better with type B viruses than type A viruses worldwide, and in the US the VE for averting outpatient illness associated with either type A or B viruses ranged in interim studies from 36-55% and was highest amongst children aged 6 months to 8 years old (Hammond, et al., 2018). While overall mortality related to influenza is hard to track as it is not a requirement to report these for adults, pediatric deaths are reported and according to the CDC there were 53 pediatric deaths related to influenza in the US in 2017-18 season. Overall, based on a new system for classifying flu season severity published in 2017, the 2017-18 flu season severity in the US was considered HIGH across all age groups (Table 1). This new system utilizes data including the percentage of visits to outpatient clinics with influenza like illness (ILI), the rates of influenza hospitalizations, and the percentage of deaths resulting from pneumonia or influenza during that season (CDCa, 2018)



Table 1: Influenza Season Severity Classifications, by Season and Age Group, United States, 2003–16


Season
Children
Adults
Older Adults
Overall
2003-04
Very High
Moderate
High
High
2004-05
Low
Moderate
Moderate
Moderate
2005-06
Low
Low
Low
Low
2006-07
Low
Low
Low
Low
2007-08
Moderate
Moderate
Moderate
Moderate
2008-09
Low
Low
Low
Low
2009-10
Very High
Moderate
Low
Moderate
2010-11
Moderate
Moderate
Moderate
Moderate
2011-12
Low
Low
Low
Low
2012-13
Moderate
Moderate
High
Moderate
2013-14ModerateModerateModerateModerate
2014-15ModerateModerateHighHigh
2015-16LowModerateLowModerate
2016-17ModerateModerateModerateModerate
2017-18HighHighHighHigh

(CDCa, 2018)


Prevention

There are two primary goals to help prevent the spread of influenza according to the CDC (CDCc, 2018). The first is everyday preventive actions that would limit the spread of any communicable disease. This includes avoiding contact with sick individuals if possible, and conversely avoiding contact with others if you are sick for at least 24 hours after fever subsides in the case of in the flu. It also includes consistent hand hygiene with either soap/water or alcohol-based hand sanitizer, covering the nose/mouth with a tissue when sneezing or coughing (and if no tissue, the “well-bow”, avoiding touching the eyes, nose, mouth or other mucous membranes, and cleaning/disinfecting surfaces and objects regularly that could be harboring bacteria/viruses (CDCc, 2018). Secondary measures to keep healthy and boost your natural immunity include getting adequate sleep, drinking adequate fluids, eating a healthy diet, and managing stress (Duncan, 2016).

The second way that the CDC recommends preventing influenza is to get vaccinated (CDCc, 2018). As healthcare professionals, this is especially important for nurses. The Advisory Committee on Immunization Practices (ACIP) recommends seasonal influenza vaccination annually for all persons over 6 months old who do not have a contraindication to vaccination. Changes for the 2018-19 season include the renewed availability of a live attenuated vaccine (FluMist) and an updated statement that any individual with a history of egg allergy may receive any licensed, recommended and age-appropriate vaccine. The appropriate ages for certain vaccines were extended (Afluria quadrivalent now safe for anyone over the age of 4, and Fluarix quadrivalent now safe over the age of 6 months). The viruses included in this year’s vaccination are:

  • A/Michigan/45/2015 (H1N1) pdm09
  • A/Singapore/INFIMH-16-0019/2016 (H3N2)
  • B/Colorado/06/2017 (Victoria lineage).

In addition, quadrivalent influenza vaccines will also contain B/Phuket/3073/2013–like virus (Yamagata lineage). Timing for vaccination is recommended by the end of October (Grohskopf, et al., 2018). Per the CDC, the only people who should not be vaccinated for the flu are babies under 6 months old, and people with severe, life-threatening allergies to flu vaccine or any ingredient in the vaccine (gelatin, antibiotics, or other ingredients) (CDCc, 2018). Those with mild egg allergies are safe to receive any flu vaccine, and those with severe egg allergies should receive their vaccines in a doctor’s office or hospital and be monitored by health care professionals for 15 minutes following vaccination for additional safety. For adults over age 65, a trivalent high-dose vaccine is recommended (Grohskopf, et al., 2018). Patients covered by Medicare should be educated that their Medicare covers the influenza vaccine, and providers should be made aware that Medicare Part B reimburses for influenza vaccines (Cannon, Bauer, Weust & Southard, 2018).

Despite the effectiveness of influenza vaccination, rates of vaccination are not as high as they should be. According to the CDC, the early vaccination rates by early November 2017 was 38.6% of persons 6 months old or older in 2017-18 (CDCb, 2017).  It is recommended that all health care workers (HCWs) get vaccinated, secondary to increased risk of exposure from patients and increased risk to patients if HCWs become infected themselves. Early season vaccination rates for HCWs was 67.6% by early November in 2017, but for nurses this rate was over 80%. Rates were lower amongst HCWs in long term care facilities and whenever employers did not require or directly recommend getting vaccinated. The internet panel survey done by CDC in November 2017 determined that HCWs who chose not to get vaccinated, made this decision due to fear of side effects or getting sick from the vaccine, thinking that they do not need the vaccine, that the ingredients in the vaccine are not good for them, or that the flu vaccine does not work (CDCa, 2017). A recent study looking at the attitudes and reasons behind nurses who declined their influenza vaccine in Switzerland found that most nurses declined because they wanted to maintain a strong and healthy body, wanted decisional autonomy, and had a general lack of trust in their environment (Pless, et al., 2017). For individuals over the age of 65, a high dose trivalent vaccine is recommended (Grohskopf, et al., 2018).


Diagnosis, Signs and Symptoms

            Influenza often presents with abrupt onset of constitutional and respiratory symptoms, including fever, cough, body aches, headache, fatigue, sore throat, and rhinitis. Unfortunately, these signs and symptoms can be difficult to differentiate many of these symptoms from a viral upper respiratory infection of another type. The fever, usually between 101-102℉, can help distinguish influenza from a cold or generic upper respiratory viral infection. In pediatric populations, nausea, vomiting, or otitis media may also be seen. Incubation period is 1-4 days, and illness typically lasts 3-7 days, although fatigue and cough may persist up to two weeks. Patients become contagious 1 day prior to symptoms presenting, and up to 7 days after becoming sick if cough and fever persist (CDCb, 2018).

            In healthy adolescents and adults under 65, a simple clinical definition such as acute fever and cough carries a predictive value of laboratory confirmed influenza between 79-88%, but in children and older adults diagnostic testing may be necessary or helpful due to atypical presentations in these age groups (CDCb, 2018). It is recommended that laboratory testing for influenza should be done when flu like symptoms are present and the test results will impact management plan. There are numerous testing options, including reverse transcriptase polymerase chain reaction (RT-PCR), rapid molecular assays, rapid influenza diagnostic tests (RIDTs), direct and indirect immunofluorescence (IF) assays, and digital immunoassays (DIAs), as well as older tests including viral cultures and serological antibody titers.  RT-PCR is the gold standard, with a sensitivity of 86-100%, but processing is usually done in special laboratories, which can take up to 8 hours, and is generally more expensive than other options. Rapid molecular assays can be done in doctors’ offices or emergency departments, with a sensitivity of 66-100% and results within 20 minutes. A recent vaccination with a live attenuated vaccine (LAIV) within the last 3-10 days may produce a false positive on these tests. RIDTs are immunoassays that detect viral nucleoprotein antigens in a respiratory specimen. Their sensitivity ranges from 50-70% and results are available in about 15 minutes, with a higher rate of false negatives. Direct/indirect IF assays require significant technical expertise and 1-2 hours of processing time to review slides under a fluorescent microscope with a sensitivity of 70-100%. DIAs create a digital process for the IF technology which eliminates the need for individual processing by a laboratory technician. They can be used in doctors’ offices or emergency departments, with results in 15 minutes, and a sensitivity of 77-80%. Viral cultures are not used clinically as they do not provide results for 3-10 days but are often used as a point of comparison in studies developing new tests (Bass, 2018). Viral cultures are also used during outbreaks to help identify the subtype and strain of virus circulating. Nasopharyngeal samples, which are required for most of the above tests, are ideally collected within three days of symptom onset (CDCb, 2018).


Complications and Management

Potential complications of influenza include worsening of underlying medical comorbidities such as asthma, congestive cardiac failure or chronic obstructive pulmonary disease (COPD) or development of lower respiratory tract disease, invasive bacterial co-infection, myocarditis, myositis, rhabdomyolysis, encephalopathy/litis, septic shock, renal failure, or respiratory failure. Those at higher risk for complications include the very young, the very old, the immunocompromised which also includes pregnant women, obese patients (BMI>40) and those with underlying medical conditions such as diabetes, asthma, etc. Of the patients hospitalized last year for influenza, over 90% of adults and 50% of children had underlying medical conditions. Within the pediatric population, increased risk of morbidity is seen in children born prematurely, or with chronic illnesses such as asthma, cystic fibrosis, metabolic diseases, and sickle cell disease (CDCb, 2018 and Cannon, Bauer, Weust & Southard, 2018).

Antiviral medications are recommended for any hospitalized or high-risk patient which include patients under 2, over 65, in long-term care facility, pregnant women, Native Americans/Alaska Natives, and immunocompromised patients, or those with underlying medical conditions such as those listed above but can also be given to previously healthy outpatients based on clinical judgment (CDCb, 2018). Antivirals should ideally be started within 48 hours of symptom onset to lessen symptom severity and shorten duration, but these medications can be expensive, require a prescription, and carry potential for adverse effects. Oseltamivir (Tamiflu), zanamivir (Relenza) and peramivir (Rabivab) are all approved by the US Food and Drug Administration (FDA) to treat influenza A or B. The most common adverse effects include nausea, vomiting, diarrhea, and headache (Cannon, Bauer, Weust & Southard, 2018). Antivirals typically shorten the duration of illness by one or two days but may more importantly decrease the rate of hospitalizations. Oseltamivir is available as a generic in either capsule or suspension form, and adverse effects of nausea and vomiting can be mitigated by counseling patients to take this medication with food (Koonin & Patel, 2018). It is also approved for chemoprophylaxis in patients over 3 months of age and is the preferred drug for pregnant patients with influenza. Zanamivir is only available as an inhaled medication for patients over the age of 7 and is not recommended in patients with underlying respiratory disease such as asthma or COPD, or in patients with severe disease. Peramivir is an intravenous medication approved for hospitalized patients over the age of 2 (CDCb, 2018). Amantadine and rimantadine are two older medication options that are still FDA-approved, but not CDC recommended as many strains of Influenza A are now resistant to these drugs (CDCb, 2018 and Koonin & Patel, 2018). There are also a wide range of over the counter medications to treat the symptoms of the flu, such as acetaminophen and/or ibuprofen for body aches and fever, and cough suppressants, expectorants, and/or decongestants for cough and runny nose symptoms. Caution should be used in giving pediatric patients decongestants or cough medications without the instructions of a pediatrician or other medical provider (Cannon, Bauer, Weust & Southard, 2018).

 

 

References

Bass III, P. F. (2018). Is it the flu? When and how to use rapid testing for influenza. Contemporary Pediatrics, 35(3), 15–20. Retrieved from http://search.ebscohost.com/login.aspx?direct=true&db=ccm&AN=128325172&site=ehost-live

Cannon, E., Bauer, R., Weust, J., & Southard, E. P. (2018). Nursing management of influenza. MEDSURG Nursing,27(2), 83-85.

Centers for Disease Control and Prevention (a). (2017, December 07). Influenza (Flu): Health Care Personnel and Flu Vaccination, Internet Panel Survey, United States, November 2017. Retrieved September 25, 2018, from https://www.cdc.gov/flu/fluvaxview/hcp-ips-nov2017.htm

Centers for Disease Control and Prevention (a). (2018, September 14). Influenza (Flu): How CDC Classifies Flu Severity. Retrieved September 25, 2018, from https://www.cdc.gov/flu/professionals/classifies-flu-severity.htm

Centers for Disease Control and Prevention (b). (2018, August 23). Influenza (Flu): Information for Health Professionals. Retrieved September 20, 2018, from https://www.cdc.gov/flu/professionals/index.htm

Centers for Disease Control and Prevention (b). (2017). Influenza (Flu): National Early-Season Flu Vaccination Coverage, United States, November 2017. Retrieved September 25, 2018, from https://www.cdc.gov/flu/fluvaxview/nifs-estimates-nov2017.htm

Centers for Disease Control and Prevention (c). (2018, September 10). Influenza (Flu): Preventive Steps. Retrieved September 25, 2018, from https://www.cdc.gov/flu/consumer/prevention.htm

Duncan, D. (2016). Stop the spread: Prevention and reduction of influenza among older individuals. British Journal of Community Nursing,21(9), 446-450. doi:10.12968/bjcn.2016.21.9.446

Grohskopf, L. A., Sokolow, L. Z., Broder, K. R., Walter, E. B., Fry, A. M., & Jernigan, D. B. (2018). Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices--United States, 2018-19 Influenza Season. MMWR Recommendations & Reports, 67(3), 1–19. Retrieved from http://search.ebscohost.com/login.aspx?direct=true&db=ccm&AN=131492779&site=ehost-live

Hammond, A., Laurenson-Schafer, H., Marsland, M., Besselaar, T., Fitzner, J., Vandemaele, K., & Wenqing Zhang. (2018). Review of the 2017-2018 influenza season in the northern hemisphere. Weekly Epidemiological Record, 93(34), 429–444. Retrieved from http://apps.who.int/iris/bitstream/handle/10665/274263/WER9334.pdf?ua=1

Koonin, L. M., & Patel, A. (2018). Timely Antiviral Administration During an Influenza Pandemic: Key Components. American Journal of Public Health, 108, S215–S220. https://doi.org/10.2105/AJPH.2018.304609

Pless, A., Mclennan, S. R., Nicca, D., Shaw, D. M., & Elger, B. S. (2017). Reasons why nurses decline influenza vaccination: A qualitative study. BMC Nursing,16(1). doi:10.1186/s12912-017-0215-5