Novel H1N1 Influenza A Current Knowledge and Recommendations June 4 2009.

Novel H1N1Novel H1N1Influenza A Influenza A

Current Knowledge and Current Knowledge and RecommendationsRecommendations

June 4 2009June 4 2009

Idaho situationIdaho situation

Currently:Currently: A total of 16 confirmed or probable A total of 16 confirmed or probable

cases in the statecases in the state 5 under investigation5 under investigation

Over 485 negative samples testedOver 485 negative samples tested Reports and samples coming in dailyReports and samples coming in daily

What criteria need to be What criteria need to be met to cause a pandemic?met to cause a pandemic?

According to CDC, a pandemic is an epidemic: According to CDC, a pandemic is an epidemic: affecting a very wide area (several countries affecting a very wide area (several countries

or continents at once) or continents at once) ANDAND affecting a larger proportion of the affecting a larger proportion of the

population than a typical epidemicpopulation than a typical epidemic Additionally, there must be:Additionally, there must be:

Ability to infect humans Ability to infect humans resulting in high resulting in high mortalitymortality

Global immunologically naïve human Global immunologically naïve human populationpopulation

Efficient human-to-human transmissionEfficient human-to-human transmission

Who declares a pandemic?Who declares a pandemic?

WHO does! WHO does! Their criteria are:Their criteria are: Phase 4Phase 4 verified human-to-human transmission of verified human-to-human transmission of

an animal or human-animal influenza reassortant an animal or human-animal influenza reassortant virus able to cause “community-level outbreaks.” virus able to cause “community-level outbreaks.”

Phase 5:Phase 5: human-to-human spread of the virus into human-to-human spread of the virus into at least two countries in one WHO region. at least two countries in one WHO region.

Phase 6Phase 6, , the pandemic phasethe pandemic phase, is characterized , is characterized by community level outbreaks in at least one other by community level outbreaks in at least one other country in a different WHO region in addition to the country in a different WHO region in addition to the criteria defined in criteria defined in Phase 5Phase 5. Designation of this . Designation of this phase will indicate that a global pandemic is under phase will indicate that a global pandemic is under way.way.

Potential Sources of New Potential Sources of New Viruses Infecting HumansViruses Infecting Humans

HumanHuman virusvirus

ReassortantReassortantvirusvirus

Diagram source: Ben Schwartz; National Vaccine Program

Belshe, R. B. N Engl J Med 2005;353:2209-2211

The Two Mechanisms whereby Pandemic Influenza Originates

The new virusThe new virus

Has genes from:Has genes from: North American swine influenza North American swine influenza avian influenza avian influenza human influenza human influenza Asian/European swine influenza Asian/European swine influenza

Never been seen before in swine or humansNever been seen before in swine or humans Different from the 1976 swine flu outbreak Different from the 1976 swine flu outbreak

virusvirus Apparently no cross-protection from the Apparently no cross-protection from the

seasonal vaccineseasonal vaccine

Clinical features so farClinical features so far

Incubation period about 2-7 daysIncubation period about 2-7 days Symptoms similar to seasonal Symptoms similar to seasonal

influenzainfluenza Complications not clear yet, with so Complications not clear yet, with so

few cases– assume the same potential few cases– assume the same potential as seasonal influenzaas seasonal influenza

High-risk groups have not yet been High-risk groups have not yet been identified, so presume “usual” groups identified, so presume “usual” groups are at high risk for now (eg elderly, are at high risk for now (eg elderly, pregnant women)pregnant women)

Infectiousness and viral Infectiousness and viral sheddingshedding

Infected persons should be assumed Infected persons should be assumed to be contagious to be contagious for at least 7 days for at least 7 days from illness onset or longer, if still illfrom illness onset or longer, if still ill. .

Some persons who are infected might Some persons who are infected might potentially shed virus and be potentially shed virus and be contagious for longer periods (e.g. contagious for longer periods (e.g. young infants, immunosuppressed, young infants, immunosuppressed, and immunocompromised persons).  and immunocompromised persons).  

Antiviral medicationsAntiviral medications

CDC shipped antiviral medications CDC shipped antiviral medications from the Strategic National from the Strategic National StockpileStockpile

Idaho received these May 1Idaho received these May 1 Tamiflu and Relenza are antiviral Tamiflu and Relenza are antiviral

influenza drugs that can make your influenza drugs that can make your illness milder and may help you feel illness milder and may help you feel better, sooner; and may prevent better, sooner; and may prevent serious influenza complicationsserious influenza complications

What is happening: What is happening: vaccinevaccine

CDC has begun working with CDC has begun working with vaccine manufacturersvaccine manufacturers

Vaccine production is meeting Vaccine production is meeting designated timelines and may be designated timelines and may be ready by about Octoberready by about October

Not certain if vaccine will ever be Not certain if vaccine will ever be recommended– depends on the recommended– depends on the course of this outbreakcourse of this outbreak

Recommendations to the Recommendations to the publicpublic

Usual respiratory etiquette Usual respiratory etiquette recommendationsrecommendations Cover nose and mouth with a tissue when Cover nose and mouth with a tissue when

coughing or sneezing, properly dispose of that coughing or sneezing, properly dispose of that tissuetissue

Wash your hands often with soap and water; Wash your hands often with soap and water; alcohol based hand cleaners are also effectivealcohol based hand cleaners are also effective

Avoid touching your eyes, nose, mouth. Germs Avoid touching your eyes, nose, mouth. Germs spread this wayspread this way

Avoid contact with sick peopleAvoid contact with sick people Stay home if you are sick for 7 days after your Stay home if you are sick for 7 days after your

symptoms begin or until you have been symptoms begin or until you have been symptom-free for 24 hours, whichever is longer.symptom-free for 24 hours, whichever is longer.

Questions??Questions??