Download 2. - Environmental Public Health Today

Pandemic Influenza Prevention
Eisha Akbar, M.D.
5/4/14
PUBH 6165
Dr. Raymond Thron
What is Influenza?
• Influenza is an RNA virus that has three types:
Influenza A, Influenza B, and Influenza C.
• Influenza A and B are the primary types that infects
humans and have two types of antigens:
hemagglutinin (H) and neuraminidase (N). 2
• There are sixteen distinct H subtypes and nine
distinct N subtypes for influenza A- as a
recombinant RNA virus, influenza viruses upon
contact with other, different influenza viruses can
reshuffle their genes and thus become more virulent
and resistant to medication.
6. Fauci et al, 2008
5. CDC, 2014
http://www.niaid.nih.gov/topics/flu/research/basic/pages/antigenicdrift
illustration.aspx
http://www.niaid.nih.gov/topics/Flu/Research/basic/Pages/AntigenicShiftIllustration.aspx
What does influenza do?
• Influenza is a respiratory virus that spreads through
respiratory droplets in the air from coughing, sneezing,
or talking by infected persons.
• The viruses attach to cells in the respiratory tract and
rapidly multiply and spread throughout the respiratory
tract.
• Symptoms include fever, myalgias, headaches, sore
throat, runny nose, and fatigue.
• The flu is generally more severe in the very young and
the very old with 90% of influenza deaths in persons who
are 65 or older.
• Those who are weakened by the flu can have a bacterial
superinfection like pneumonia which can result in death.
6. Fauci et al, 2008
Risk Factors
• Children younger than five (especially those
younger than 2)
• People aged 65 or older
• Pregnant women
• Native Americans and Alaskan Natives
• Persons with asthma,
neurological/neurodevelopmental disorders,
chronic lung disease, heart failure, metabolic
disorders, immunosuppression, morbid obesity,
kidney disorders, and more
6. Fauci et al, 2008
Prevention and Treatment
• Influenza vaccine is available during the flu season from
October-March.
▫ There are trivalent shots, quadrivalent shots, trivalent shots
without egg, and quadrivalent nasal spray
▫ Recommended for children age 6 months to 59 months
▫ Recommended for those 50 and older
▫ Nursing home residents and healthcare personnel have increased
exposure and therefore require vaccination
• Antiviral drugs
▫ Primary drugs being oseltamivir and zanamivir; active against
both type A and type B. Amantadine is no longer effective (Fauci
et al, 2008)
▫ Oseltamivir can be used on patients of any age while zanamivir is
approved for those aged 7 years and older.
▫ Antiviral drugs are used in severe cases, otherwise treatment is
usually supportive.
5. CDC, 2014
6. Fauci et al, 2008
History of pandemic influenza
• The most infamous influenza pandemic was the Spanish flu
which occurred between 1917 and 1918, killing around 40
million people, especially the young and healthy (WHO,
2003)
▫ Risk factors during that time included being between 25-29,
military service, chest circumference being 90-100+ cm
(Summers et al, 2014)
• Two other pandemics, Asian influenza in 1957 (H2N2) and
Hong Kong influenza (H3N2) in 1968 were not as severe as
Spanish flu but was found to have increased mortality in
young people. (WHO, 2003, Fauci et al, 2008)
• It is difficult to estimate how many people die of influenza
each year, but the 2012-2013 season showed 42 admissions
for every 100,000 years, which increased from 7.7-23.4 per
100,000 in the previous three seasons (Bresee et al, 2013)
Avian Flu
• Avian flu is an influenza A type virus that is found in birds all over
the world, having been isolated from 100 different bird species
(CDC)
• H7N9 was reported in China in March of 2013, found in infected
poultry with human crossover, although there was no human to
human transmission
▫ 44 deaths resulted of H7N9 during spring of 2013
▫ Increased frequency of H7N9 began in October 2013
• Highly pathogenic H5N1 (HPAI H5N1) usually kills what fowl or
poultry it infects and has human crossover from animals and has
resulted in death.
▫ Because H5N1 is seriously pathogenic, there are restrictions on the
importation of poultry from countries where outbreaks are common
▫ There are currently stockpiles of vaccines against HPAI H5N1 should the
virus easily begin to transfer from human to human and cause an
outbreak
5. CDC, 2014
Swine Flu
• Swine flu is a type A influenza virus found primarily
in pigs with the main viruses being H1N1, H3N2,
and H1N2. Infection in humans is known as “variant
influenza viruses”.
• Those infected with variant influenza are usually
those who work closely with pigs.
• H1N1 in 2009 was found in humans in April of 2009
was declared a “public health emergency” by the
WHO later that month. (Young et al, 2013)
▫ Due to air travel, at least five cases were found on
commercial air flights to the UK.
5. CDC, 2014
H1N1 Pandemic of 2009
• First reported to who as “influenza-like illness” in the US and
Mexico on 24th April, 2009
• By 30th April, 11 countries had reported incidence of H1N1
cases, totaling 257 cases
• By June 3rd, 19,273 cases were reported in 66 countries with
117 deaths, 97 of them being in Mexico
• On July 31st, 2009, 168 countries and territories had reported
at least one case of H1N1 with 162,380 cases and 1154 deaths.
• On July 30th, 2010, 214 countries and territories had reported
over 18,000 cumulative deaths from H1N1
• H1N1 cases were decreasing by summer of 2010 but were still
very active in New Zealand and India
• By 10th September 2010, WHO relegated H1N1 as postpandemic
15. WHO, 2010
Ongoing Surveillance
• WHO Global Influenza Surveillance and Response
System
▫ Monitors virus changes, provides recommendations for lab
procedures, vaccines, risk assessment
▫ If needed, gives out a global alert
▫ Monitors for antiviral susceptibility and resistance
▫ Has National Influenza Centres (NIC) to collect reports and
analyses of viruses in nations around the world
• Epidemiology and Prevention Branch of Influenza
Division of the CDC in the United States
▫ Finds and tracks influenza activity, determines virus type,
discovers virus changes, and measures the impact of
hospitalizations and deaths.
▫ Virological surveillance in tandem with WHO
12. WHO, 2014
4. CDC, 2014
Are we prepared?
• While H1N1 resulted in deaths and caused the WHO to
announce it as a worldwide public health issue, H1N1 did not
have strong virulence.
• Vaccine availability against H1N1 was low after it was
announced as a pandemic and was only available in ample
supply after October.
• Antiviral drug production is not currently up to where there
would be enough in the case of a pandemic and some virus
strains may be resistant.
• Areas of low resource are at higher risk as supply lines may
halt to prevent spread, leaving insufficient amounts of food,
medicine, and health care workers
• Non-pharmaceutical interventions such as hand washing and
isolation may be of some assistance (Starbuck et al, 2013)
So what is being done?
Actions of the WHO
• Global Action Plan for Influenza Vaccines
▫ Objective 1 is to increase vaccination use and policy in countries,
objective 2 is to increase pandemic vaccine production and to
vaccination 70% of the world’s population, and objective 3 is to
develop better vaccines and improve the speed at which they are
developed.
▫ From institution in 2006 to 2013, GAP shows global vaccine
production capacity increase to 1.5 billion, increased
manufacturing bases in low and middle income countries,
increased number of countries that vaccinate at risk groups from
46 to 72, and at least 380 clinical trials of pandemic vaccines.
• FluNet
▫ “Global tool for influenza virological surveillance”
▫ Collects data from NICs and regional WHO databases
▫ 10,986 specimens positive for influenza, 67.4% being influenza A
and 32.6% being influenza B.
10. WHO, 2014
12. WHO, 2014
13. World Health Organization (WHO). (2014). Percentage of respiratory specimens that tested positive for influenza, by influenza
transmission zone (image). Retrieved from
http://www.who.int/influenza/surveillance_monitoring/updates/2014_04_07_influenza_update_208_week_12.jpg?ua=1
Actions of the CDC
• FluView
▫ Provides weekly surveillance reports on influenza activity
▫ Obtains data from hospitals, laboratories, and public health services and
is prepared to alert country and WHO in case of epidemic
▫ Has found 8,995 laboratory confirmed cases of hospitalizations due to
influenza
▫ H3N2, H1N1, and influenza B viruses have all been reported in the 20132014 season
▫ Highest percentage of cases were in week 52 of 2013 and has steadily
decreased since
• National Influenza Vaccination Week
▫ Took place December 8-14th, 2013.
▫ Works to shine a spotlight on influenza and the importance of
vaccination through social media, vaccination clinics, newspaper and
magazine articles, and news programs
3. CDC, 2013
4. CDC, 2014
4. Centers for Disease Control and Prevention (CDC). (2014). FluView: A Weekly
Influenza Surveillance Report Prepared by the Influenza Division.
http://www.cdc.gov/flu/weekly/index.htm#OISmap
4. Centers for Disease Control and Prevention (CDC). (2014). FluView: A Weekly Influenza Surveillance Report Prepared by the Influenza
Division. http://www.cdc.gov/flu/weekly/index.htm#OISmap
Prevention Methods
• Influenza vaccine
▫ For both those at risk and the healthy- herd immunity
protects us all.
• Hand washing, with increased frequency in those
exposed to the sick
• Covering nose and mouth when sneezing and
coughing
• Staying home when sick to prevent further spread
• Disinfecting surfaces
• Stop smoking
• Canceling mass gatherings or closing schools when
there is a large amount of illness.
2. CDC, 2012
Cost Effectiveness of Prevention
• School closure + antiviral drugs + vaccine
prophylaxis are the most cost effective strategies.
• Prophylaxis is key as vaccination can reduce severity
of symptoms and time of disease.
• Severe pandemic: ~$9 per life year saved
▫ Reduced social contact (closed schools, no mass
gatherings, closed crowded workplaces) and antiviral
drugs cut down on cost
▫ Costs are usually a result of hospitalizations and
deaths
• Low severity pandemic: ~$58 per life year saved
▫ Costs result of productivity losses due to people
staying at home due to illness.
7. Milne et al, 2013
What have we learned?
• Influenza is constant presence in the world of illness
with the season usually lasting from October to
March.
• There have been severe historical pandemics that
have resulted in huge losses of life.
• We have vaccines and antiviral drugs available to
prevent and treat influenza.
• There are many daily activities we can perform to
prevent ourselves from catching the flu.
• Staying at home when ill is best to prevent further
spread of disease.
THE END
Any Questions?
References
1. Bresee, J., Reed, C., Kim, I.K., Finelli, L., Fry, A., Chaves, S.S., Burns, E., Garuillo, P., Jernigan, D., Cox, N.,
Singleton, J., Zhai, Y., O’Halloran, A., Kahn, K., Lu, P-J., Santibanez, T. (2013). Estimated Influenza Illnesses
and Hospitalizations Averted by Influenza Vaccination — United States, 2012–13 Influenza Season.
Morbidity and Mortality Weekly Report. 62(49): 997-1000. Retrieved from
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6249a2.htm
2. Centers for Disease Control and Prevention (CDC). (2012). Nonpharmaceutical Interventions (NPIs).
Retrieved from http://www.cdc.gov/nonpharmaceutical-interventions/
3. Centers for Disease Control and Prevention (CDC). (2013). National Influenza Vaccination Week.
Retrieved from http://www.cdc.gov/flu/nivw/index.htm
4. Centers for Disease Control and Prevention (CDC). (2014). FluView: A Weekly Influenza Surveillance
Report Prepared by the Influenza Division. http://www.cdc.gov/flu/weekly/index.htm#OISmap
5. Centers for Disease Control and Prevnetion (CDC). (2014). Seasonal Influenza (Flu). Retrieved from
http://www.cdc.gov/flu/about/disease/index.htm
6. Fauci, A.S., Kasper, D.L., Longo, D.L., Brauwald, E., Hauser, S.L., Jameson, J.L., Loscalzo, J. (2008).
Harrison’s Principles of Internal Medicine, 17th ed. New York City , NY: McGraw Hill.
7. Milne, G.J., Halder, N., Kelso, J.K. (2013). The Cost Effectiveness of Pandemic Influenza Interventions: A
Pandemic Severity Based Analysis. PLoS One. 8(4):e61504. doi:10.1371/journal.pone.0061504. Retrieved
from http://web.b.ebscohost.com.ezp.waldenulibrary.org/ehost/pdfviewer/pdfviewer?sid=0194aa2c-fd9e46f2-935a-b6658547d7d3%40sessionmgr113&vid=8&hid=128
8. Starbuck, E.S., von Bernuth, R., Bolles, K., Koepsell, J. (2013). Are we prepared to help low-resource
communities cope with a severe influenza pandemic? Influenza and Other Respiratory Viruses. 7(6): 909913. Retrieved from
http://web.b.ebscohost.com.ezp.waldenulibrary.org/ehost/pdfviewer/pdfviewer?sid=ca8d283b-4f86-483a8372-753252af3da0%40sessionmgr112&vid=2&hid=128
References
9. Summers, J.A., Stanley, J., Baker, M.G., Wilson, N. (2014). Risk factors for death from Pandemic
influenza in 1918-1919: a case control study. Influenza and Other Respiratory Viruses. 8(3): 329-338.
Retrieved from
http://web.b.ebscohost.com.ezp.waldenulibrary.org/ehost/pdfviewer/pdfviewer?sid=2c015b38-7921-4bfaa040-96a310c41847%40sessionmgr115&vid=2&hid=128
10. World Health Organization (WHO). (2014). FluNet Summary. Retrieved from
http://www.who.int/influenza/gisrs_laboratory/updates/summaryreport/en/
11. World Health Organization (WHO). (2014). Global Action Plan for Influenza Vaccines: Global Progress
Report January 2006-September 2013). Geneva, Switzerland: WHO Press.
http://apps.who.int/iris/bitstream/10665/112307/1/9789241507011_eng.pdf?ua=1
12. World Health Organization (WHO). (2014). Global Influenza Surveillance and Response System
(GISRS). Retrieved from http://www.who.int/influenza/gisrs_laboratory/en/
13. World Health Organization (WHO). (2014). Percentage of respiratory specimens that tested positive for
influenza, by influenza transmission zone (image). Retrieved from
http://www.who.int/influenza/surveillance_monitoring/updates/2014_04_07_influenza_update_208_we
ek_12.jpg?ua=1
14. World Health Organization (WHO). (2003). Influenza. Retrieved from
http://www.who.int/mediacentre/factsheets/2003/fs211/en/
15. World Health Organization (WHO). (2010). Situation Updates- Pandemic (H1N1) 2009. Retrieved from
http://www.who.int/csr/disease/swineflu/updates/en/
16. Young, N, Pebody, R., Smith, G., Olowokure, B., Shankar, G., Hoschler, K., Galiano, M., Green, H.,
Wallensten, A., Hogan, A., Oliver, I. (2014). International flight related transmission of pandemic influenza A
(H1N1)pdm09: an historical cohort study of the first identified cases in the United Kingdom. Influenza and
Other Respiratory Viruses. 8(1): 66-73. Retrieved from
http://web.b.ebscohost.com.ezp.waldenulibrary.org/ehost/pdfviewer/pdfviewer?sid=8b6da3de-998e-49348fe3-9f26925991a5%40sessionmgr114&vid=2&hid=128
References
17. Antigenic Drift. (2011). National Institute of
Allergy and Infectious Diseases. Retrieved from
http://www.niaid.nih.gov/topics/flu/research/ba
sic/pages/antigenicdriftillustration.aspx
18. Antigenic Shift. (2011). National Institute of
Allergy and Infectious Diseases. Retrieved from
http://www.niaid.nih.gov/topics/Flu/Research/b
asic/Pages/AntigenicShiftIllustration.aspx