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Influenza: Is Pregnancy an Infection Risk?. Vicky R. Zelenka Infection Preventionist Legal Nurse Consultant. Goals of Presentation. Identify the impact pregnancy has on influenza infection risk/complications List prevention and control strategies for influenza in pregnant population.
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Influenza: Is Pregnancy an Infection Risk? Vicky R. Zelenka Infection Preventionist Legal Nurse Consultant
Goals of Presentation • Identify the impact pregnancy has on influenza infection risk/complications • List prevention and control strategies for influenza in pregnant population
What is Influenza? Influenza is a very significant acute upper respiratory tract infection caused by influenza viruses. Influenza can occur year round but usually occurs in winter and spring.
Pathology of Influenza • Virus attaches to and penetrates respiratory epithelial cells in trachea and bronchi • Virus replicates and destroys host cell • Symptoms occur but viremia absent • Virus shed in respiratory secretions for 5-10 days, runs course in 2 weeks.
Signs and Symptoms of Influenza • IMMEDIATE onset of muscle aches, fatigue and high fever. Also includes cough, sore throat, headache, chills, nonproductive cough, conjunctivitis, runny nose. • In children, diarrhea and seizures
Definition of Close Contact • Having cared for or lived with a person who has confirmed, probable, or suspected influenza, or having cared for or lived with a person with confirmed, probable or suspected influenza. Also includes being in setting where there was a high likelihood of contact with respiratory droplets and/or body fluids of sick people. CDC - 2009
Influenza Transmission – Close Contact • Coughing, sneezing into air • Inhaling infected air • Kissing or sharing handkerchiefs/tissues • Sharing eating utensils/sharing food • Touching contaminated smooth surfaces (door knobs, handles, telephones)
High Risk Groups • Groups at high risk for complications secondary to influenza are those with: Chronic lung disease, diabetes mellitus, chronic renal failure, cardiac disease, immunosuppressed, those in residential homes and LTC facilities.
Morbidity/Mortality • 1979 through 2001 – Annual influenza related hospitalizations = 226,000 • 1979 through 1990 – Annual influenza associated deaths = 19,000/yr • 1990-1999 – Annual influenza associated deaths = 36,000/yr (8,000 due to influenza associated pneumonia)
Pandemic vs Epidemic Influenza
Pandemic Influenza • Pandemic occurs when: • new influenza type-A virus emerges (antigenic shift) - no immunity in population - virus spreads efficiently between humans - results in worldwide outbreaks of disease
Recent Pandemics • 1889 pandemic • 1918 – 1919 Spanish pandemic (influenza virus type H1) • 1957 - subtype H2N2 • 1968 – 1969 Hong Kong H2N2 • 1977 Russian subtype H1N1 • 2009 H1N1
Epidemic Influenza • Type A or B influenza virus appearing in groups or clusters • Virus is not new virus • Vaccine usually available • Post exposure prophylaxis available
Influenza Virus Vaccines • Inactivated influenza virus vaccine - Prepared annually - No live virus in vaccine - Injectable - 2 doses for children with zero prior influenza vaccination
Live attenuated virus vaccine (LAV) • Live weakened flu vaccine • Intranasal administration • Limited to healthy individuals • Not administered to children under 2 yo. • Two doses for children with zero prior influenza vaccination • Vaccine for 2 years and younger Thimerosol- free
19 flu seasons - 4,300 women of child bearing age – Pregnant women 5 times more likely than post-partum patients to requirehospitalization – (Am J Epidemiology-1998) • 1970’s – 3 flu seasons rates of medical visits for acute resp. disease more than twice as high in pregnant vs. non-pregnant. (Public Health Report 1986)
Routine Vaccines for Pregnant Patients • Hepatitis A & B • Influenza (inactivated) • Tetanus/Diphtheria or T dap (2nd or 3rd trimester) • Meningococcal • Rabies ACIP Guidelines – May 2008
Why does pregnancy appear to increase risk of influenza complications? • Mechanical & hormonal changes associated with pregnancy • Decreased lung capacity • Changes in the cardiovascular system
1 • Altered immune response due to pregnancy---shift away from cell mediated immunity • Hospitalization for women 37-42 weeks gestation = 5 fold compared to women one to six months post partum • Greatest risk in 3rd trimester
Use of Antiviral • Start anti-viral treatment immediately if influenza suspected. • Antivirals MOST effective when given within 48 hours of symptoms • BUT, start ASAP even if beyond 48 hrs.
Prophylaxis during Pregnancy • No evidence of adverse effects of antiviral use (Tamiflu) in pregnant female. • Better to treat than risk increased illness in pregnant female. CDC 2007
Influenza and the Neonate • Flu vaccine risk to infants quite low • Some studies show vaccine protects mother and infant (NEJM – 2008) • Virus does not appear to pass through placenta • Neonatal problems associated with maternal inflammatory process & fever (Int J Dev Neuroscience – 2003)
2009 H1N1 Influenza Lessons Learned • Number of new cases declined with vaccine, prevention strategies and post- exposure management. • 99% of serotype Influenza type A were H1N1 • H1N1 vaccine supply started below expected level but increased mid-season
Lessons Learned cont’d. • Ongoing surveillance did not reveal unusual adverse effects associated with vaccine • Child deaths from H1N1 in otherwise healthy children associated with co-infection with bacteria, usually Staphylococcus or Pneumococcal pneumonia.
H1N1 Transmission from Humans to Pets • Four cases of lab confirmed H1N1 have appeared in cats and ferrets. • Household members symptomatic for H1N1 • Animals had lung consolidation or pleural effusion • Prevention strategies for sick in home should be followed with pets. International Conference on Emerging Infectious Disease, July 12, 2010
2010-2011 Seasonal Vaccine Recommendation Changes • Recommends 6 mo and older (previously 19-49 yo.) • Vaccine dose (under 8 yo) related to # vaccine doses received in 2009. • 2010-2011 vaccine includes 2 A viruses and one B virus. (H1N1 included). (CDC MMWR July 29 2010)
Conclusions • Influenza is a seasonal viral infection that affect males and females, young & old, pregnant and non pregnant. • Influenza vaccine should be taken by all eligible consumers • Implement prevention/control policies including hand hygiene, including pets • Avoid close contact with infected • Administer antivirals following exposure
Preventing Influenza • Hand hygiene • Vaccine • Post-exposure prophylaxis for all exposed including pregnant • Home quarantine in epidemics • ER/MD office segregation sick/pregnant