Novel H1N1 (Swine) Epidemiology & Control

Ahmed MandilProf of EpidemiologyDept of Family & Community MedicineCollege of Medicine, King Saud University

Avian Flu

Influenza VirusDefinitionsIntroductionSpread/Transmission Timeline/FactsResponse Case-DefinitionsTreatmentOther Protective MeasuresConclusion & Recommendations

HEADLINES

Credit: L. Stammard, 1995Virus

Epidemic a located cluster of casesPandemic worldwide epidemicAntigenic driftChanges in proteins by genetic point mutation & selection Ongoing and basis for change in vaccine each yearAntigenic shift Changes in proteins through genetic reassortmentProduces different viruses not covered by annual vaccineDefinitions General

Lessons Learned formPast PandemicsFirst outbreaks March 1918 in Europe, USAHighly contagious, but not deadlyVirus traveled between Europe/USA on troop shipsLand, sea travel to Africa, AsiaWarning signal was missedAugust, 1918 simultaneous explosive outbreaks in in France, Sierra Leone, USA10-fold increase in death rateHighest death rate ages 15-35 yearsCytokine Storm?Deaths from primary viral pneumonia, secondary bacterial pneumoniaDeaths within 48 hours of illnessCoincident severe disease in pigs20-40 million killed in less than 1 yearWorld War I 8.3 million military deaths over 4 years25-35% of the world infected

Pandemics are unpredictableMortality, severity of illness, pattern of spreadA sudden, sharp increase in the need for medical care will always occurCapacity to cause severe disease in nontraditional groups is a major determinant of pandemic impactEpidemiology reveals waves of infectionAges/areas not initially infected likely vulnerable in future wavesSubsequent waves may be more severe1918- virus mutated into more virulent form1957 schoolchildren spread initial wave, elderly died in second wavePublic health interventions delay, but do not stop pandemic spreadQuarantine, travel restriction show little effectDoes not change population susceptibilityDelay spread in Australia later milder strain causes infection thereTemporary banning of public gatherings, closing schools potentially effective in case of severe disease and high mortality Delaying spread is desirableFewer people ill at one time improve capacity to cope with sharp increase in need for medical care

Lessons Learned formPast Pandemics

Swine Influenza A(H1N1) IntroductionSwine Influenza (swine flu) is a respiratory disease of pigs caused by type A influenza that regularly cause outbreaks of influenza among pigs

Most commonly, human cases of swine flu happen in people who are around pigs

Swine flu viruses do not normally infect humans, however, human infections with swine flu do occur, and cases of human-to-human spread of swine flu viruses have been documented

Swine Influenza A(H1N1) Transmission to HumansThrough contact with infected pigs or environments contaminated with swine flu viruses

Through contact with a person with swine flu

Human-to-human spread of swine flu has been documented also and is thought to occur in the same way as seasonal flu, through coughing or sneezing of infected people

Swine Influenza A(H1N1) Transmission Through Species

Reassortment in Pigs

Swine Influenza A(H1N1) FactsVirus described as a new subtype of A/H1N1 not previously detected in swine or humans

CDC determines that this virus is contagious and is spreading from human to human

The virus contains gene segments from 4 different influenza types: North American swineNorth American avianNorth American human and Eurasian swine

Swine Influenza A(H1N1) Global ResponseThe WHO raises the alert level to Phase 6WHOs alert system was revised after Avian influenza began to spread in 2004 Alert Level raised to Phase 3In Late April 2009 WHO announced the emergence of a novel influenza A virus April 27, 2009: Alert Level raised to Phase 4April 29, 2009: Alert Level raised to Phase 5June 11, 2008:Alert Level raised to Phase 6

Source: WHO

GLOBALLY: March 1-December 23 At least 11,516 Deaths Africa Region (AFRO): 109Americas Region (AMRO): 6,670 Eastern Mediterranean Region (EMRO): 663Europe Region (EURO) :2,045South-East Asia Region (SEARO): 990 Western Pacific Region (WPRO) :1,039

Source: WHOSwine Influenza A(H1N1) Status UpdateECDC reported a total of 12,776 deaths December 28, 2009

Swine Influenza A(H1N1) CDC Estimates from April-November 14, 2009, By Age GroupSource: CDC. http://www.cdc.gov/h1niflu/surveillanceqa.htm

2009 H1N1Mid-Level Range*Estimated Range *Cases0-17 years~16 million~12 million to ~23 million18-64 years~27 million~19 million to ~38 million65 years and older~4 million~3 million to ~6 millionCases Total~47 million~34 million to ~67 millionHospitalizations0-17 years~71,000~51,000 to ~101,00018-64 years~121,000~87,000 to ~172,00065 years and older~21,000~15,000 to ~29,000Hospitalizations Total~213,000~154,000 to ~303,000Deaths0-17 years~1,090~790 to ~1,55018-64 years~7,450~5,360 to ~10,57065 years and older~1,280~920 to ~1,810Deaths Total~9,820~7,070 to ~13,930

Pandemic (H1N1) 2009 in the EMR as of 6 November, 200922/22 countries affectedRegular reports from 17 countries: 26,400 confirmed cases and 150 deaths.Localized to moderate geographical distribution.Increasing trend in most of the countriesLow to moderate intensity Low to moderate impact on the health system

CountryCumulative number of confirmed casesCumulative number of deathsTrendKuwait6, 64017IncreasingUAE790NABahrain7936NALebanon7612NAEgypt1, 5925IncreasingSaudi Arabia4, 11928NAPalestine 7771IncreasingMorocco4840IncreasingJordan2, 0503Increasing Qatar231NAYemen62917IncreasingOman3, 32925IncreasingIran1, 63822IncreasingTunisia1, 2850IncreasingIraq1, 0807IncreasingLibya210UnchangedSyria1606IncreasingAfghanistan77210IncreasingSudan70Unchanged Pakistan50UnchangedDjibouti90UnchangedSomalia20UnchangedTotal26,400150

Pandemic H1N1 2009 in the EMR as of 6 November, 2009

Avian Flu

The Epidemic CurveSingle-wave profile showing proportion of new clinical cases, consultations, hospitalisations or deaths by week. Based on London, second wave 1918. 0%5%10%15%20%123456789101112WeekProportion of total cases, consultations, hospitalisations or deaths InitiationAccelerationPeakDecline

Aims of community reduction of influenza transmission mitigationDelay and flatten epidemic peak.Reduce peak burden on healthcare system and threat.Somewhat reduce total number of cases. Buy a little time.DailycasesDays since first caseNo intervention

Swine Influenza A(H1N1) Mediterranean & Middle East Confirmed Deathsn=1,246Source: ECDCAs of December 28, 2009

Global Distribution of Reported Laboratory Confirmed Cases & Deaths of Swine Influenza A(H1N1), December 23, 2009 Source: WHO

Geographic Spread of Influenza ActivityBased Upon Country Reporting, Week 50, 2009 (07-23 December)Source: WHO

Impact on Healthcare Services Based Upon Degree of Disruption, As a Result of Acute Respiratory DiseasesWeek 50, 2009 (07-13 December)Source: WHO

Number of Specimens Positive for Influenza Sub-TypeSource: CDC

Laboratory-Confirmed Cases & Deaths of New Influenza A(H1N1) by WHO Regions, September 20, 2009 *Given that countries are no longer required to test and report individual cases, the number of cases reported actually understates the real number of cases. At least 318,925 Cases & Over 3917 DeathsOverall Case-Fatality Rate (CFR) in Confirmed ~ 1.2%Source: WHOCFR = 0.5%CFR = 2.5%CFR = 0.6%CFR = 1.1%CFR = 0.3%CFR = 0.4%

Swine Influenza A(H1N1) Guidelines for General PopulationCovering nose and mouth with a tissue when coughing or sneezingDispose the tissue in the trash after use. Handwashing with soap and waterEspecially after coughing or sneezing. Cleaning hands with alcohol-based hand cleaners Avoiding close contact with sick peopleAvoiding touching eyes, nose or mouth with unwashed handsIf sick with influenza, staying home from work or school and limit contact with others to keep from infecting them

Comparison of Available Influenza Diagnostic Tests1 Source: CDC

Influenza Diagnostic TestsMethodAvailabilityTypicalProcessing Time2Sensitivity3 for2009 H1N1influenzaDistinguishes 2009 H1N1 influenza from other influenza A viruses?Rapid influenza diagnostic tests (RIDT)4Antigen detectionWide0.5 hour10 70%NoDirect and indirectImmunofluorescenceassays (DFA and IFA)5Antigen detectionWide2 4 hours4793%NoViral isolation in tissue cellcultureVirus isolationLimited2 -10 days-Yes 6Nucleic acid amplification tests (including rRT-PCR) 7RNA detectionLimited848 96 hours [6-8 hours toperform test]86 100%Yes

Avian Flu

There are two flu antiviral drugs recommendedOseltamivir or Zanamivir Use of anti-virals can make illness milder and recovery faster

They may also prevent serious flu complications

For treatment, antiviral drugs work best if started soon after getting sick (within 2 days of symptoms)

Warning! Do NOT give aspirin (acetylsalicylic acid) or aspirin-containing products (e.g. bismuth subsalicylate Pepto Bismol) to children or teenagers (up to 18 years old) who are confirmed or suspected ill case of swine influenza A (H1N1) virus infection; this can cause a rare but serious illness called Reyes syndrome. For relief of fever, other anti-pyretic medications are recommended such as acetaminophen or non steroidal anti-inflammatory drugs.

Treatment is recommended for: All hospitalized patients with confirmed, probable or suspected novel influenza (H1N1). Patients who are at higher risk for seasonal influenza complicationsIf patient is not in a high-risk group or is not hospitalized, healthcare providers should use clinical judgment to guide treatment decisions

Swine Influenza A(H1N1) Antiviral ProtectionSource: CDC

Antiviral Chemoprophylaxis for Treatment: Post-exposure: Duration chemoprophylaxis is 10 days after the last known exposure to novel (H1N1) influenza and may be considered in the following: Close contacts of cases (confirmed, probable, or suspected)Health care personnel, public health workers, or first responders who have had a recognized, unprotected close contact exposure to a person (confirmed, probable, or suspected) during that persons infectious period.

Pre-exposure: Antivirals should only be used in limited circumstances, and in consultation with local medical or public health authorities.

Antiviral Use for Control of Novel H1N1 Influenza OutbreaksA cornerstone for the control of seasonal influenza outbreaks in nursing homes and other long term care facilities. If outbreaks were to occur, it is recommended that ill patients be treated with oseltamivir or zanamivir and that chemoprophylaxis with either oseltamivir or zanamivir be started as early as possible to reduce the spread of the virus as is recommended for seasonal influenza outbreaks in such settings.

Children Under 1 Year of AgeOseltamivir is not licensed for use in children less than 1 year of age. Because infants experience high rates of morbidity and mortality from influenza, infants with novel (H1N1) influenza virus infections may benefit from treatment using oseltamivir.

Swine Influenza A(H1N1) Antiviral ProtectionSource: CDC

Source: CDCDosing recommendations for antiviral treatment of children younger than 1 year using oseltamivir. Recommended treatment dose for 5 days.

Novel H1N1 vaccine available for since Mid-September

Seventh Harvard Pandemic Survey 38% of Children in the US immunized50% Adults do not intend to be immunized35% of parents do not intend to get their children immunized

Novel H1N1 vaccine is not intended to replace the seasonal flu vaccine it is intended to be used along-side seasonal flu vaccine

Vaccines:Inactivated influenza virus vaccinesCSL Ltd. of Australia Novartis Vaccines of Switzerland Sanofi Pasteur of France 800,000 pre-filled syringes were recalled are for young children, ages 6 months to 3 years in the USGlaxoSmithKline (GSK) of UKSinovac Biotech of ChinaLive-attenuated virus vaccineMedImmune LLC of US (nasal-spray)4.5 million doses recalled due to decreased potency in the USSwine Influenza A(H1N1) Vaccine Protection

CDCs Advisory Committee on Immunization Practices (ACIP) recommends the following groups to receive the novel H1N1 influenza vaccine:

Pregnant women because they are at higher risk of complications and can potentially provide protection to infants who cannot be vaccinated;

Household contacts and caregivers for children younger than 6 months of age because younger infants are at higher risk of influenza-related complications and cannot be vaccinated. Vaccination of those in close contact with infants less than 6 months old might help protect infants by cocooning them from the virus;

Healthcare and emergency medical services personnel because infections among healthcare workers have been reported and this can be a potential source of infection for vulnerable patients. Also, increased absenteeism in this population could reduce healthcare system capacity;

All people from 6 months through 24 years of age

Children from 6 months through 18 years of age because we have seen many cases of novel H1N1 influenza in children and they are in close contact with each other in school and day care settings, which increases the likelihood of disease spread, and

Young adults 19 through 24 years of age because we have seen many cases of novel H1N1 influenza in these healthy young adults and they often live, work, and study in close proximity, and they are a frequently mobile population; and,

Persons aged 25 through 64 years who have health conditions associated with higher risk of medical complications from influenza.

Swine Influenza A(H1N1) Vaccine ProtectionSource: CDC

Swine Influenza A(H1N1): Face Mask and Respirator ProtectionSource: CDC

SettingPersons not at increased risk of severe illness from influenza(Non-high risk persons)Persons at increased risk of severe illness from influenza (High-Risk Persons)CommunityNo 2009 H1N1 in communityFacemask/respirator not recommendedFacemask/respirator not recommended2009 H1N1 in community: not crowded settingFacemask/respirator not recommendedFacemask/respirator not recommended2009 H1N1 in community: crowded settingFacemask/respirator not recommendedAvoid setting. If unavoidable, consider facemask or respiratorHomeCaregiver to person with influenza-like illnessFacemask/respirator not recommendedAvoid being caregiver. If unavoidable, use facemask or respiratorOther household members in homeFacemask/respirator not recommendedFacemask/respirator not recommendedOccupational (non-health care)No 2009 H1N1 in communityFacemask/respirator not recommendedFacemask/respirator not recommended2009 H1N1 in communityFacemask/respirator not recommended but could be considered under certain circumstancesFacemask/respirator not recommended but could be considered under certain circumstancesOccupational (health care)Caring for persons with known, probable or suspected 2009 H1N1 or influenza-like illness RespiratorConsider temporary reassignment. Respirator

Avian Flu

Swine Influenza A(H1N1) Other Protective MeasuresDefining Quarantine vs. Isolation vs. Social-Distancing Isolation: Refers only to the sequestration of symptomatic patents either in the home or hospital so that they will not infect others

Quarantine: Defined as the separation from circulation in the community of asymptomatic persons that may have been exposed to infection

Social-Distancing: Has been used to refer to a range of non-quarantine measures that might serve to reduce contact between persons, such as, closing of schools or prohibiting large gatheringsSource: CDC

Swine Influenza A(H1N1) Other Protective MeasuresPersonnel Engaged in Aerosol Generating Activities CDC Interim recommendations:Personnel engaged in aerosol generating activities (e.g., collection of clinical specimens, endotracheal intubation, nebulizer treatment, bronchoscopy, and resuscitation involving emergency intubation or cardiac pulmonary resuscitation) for suspected or confirmed swine influenza A (H1N1) cases should wear a fit-tested disposable N95 respirator

Pending clarification of transmission patterns for this virus, personnel providing direct patient care for suspected or confirmed swine influenza A (H1N1) cases should wear a fit-tested disposable N95 respirator when entering the patient room

Respirator use should be in the context of a complete respiratory protection program in accordance with Occupational Safety and Health Administration (OSHA) regulations. Source: CDC

Infection Control of Ill Persons in a Healthcare Setting

Patients with suspected or confirmed case-status should be placed in a single-patient room with the door kept closed. If available, an airborne infection isolation room (AIIR) with negative pressure air handling with 6 to 12 air changes per hour can be used. Air can be exhausted directly outside or be recirculated after filtration by a high efficiency particulate air (HEPA) filter. For suctioning, bronchoscopy, or intubation, use a procedure room with negative pressure air handling.

The ill person should wear a surgical mask when outside of the patient room, and should be encouraged to wash hands frequently and follow respiratory hygiene practices. Cups and other utensils used by the ill person should be washed with soap and water before use by other persons. Routine cleaning and disinfection strategies used during influenza seasons can be applied to the environmental management of swine influenza. Swine Influenza A(H1N1) Other Protective MeasuresSource: CDC

Infection Control of Ill Persons in a Healthcare Setting

Standard, Droplet and Contact precautions should be used for all patient care activities, and maintained for 7 days after illness onset or until symptoms have resolved. Maintain adherence to hand hygiene by washing with soap and water or using hand sanitizer immediately after removing gloves and other equipment and after any contact with respiratory secretions.

Personnel providing care to or collecting clinical specimens from suspected or confirmed cases should wear disposable non-sterile gloves, gowns, and eye protection (e.g., goggles) to prevent conjunctival exposure.Swine Influenza A(H1N1) Other Protective MeasuresSource: CDC

SummaryWHO raised the alert level to Phase 6 on June 11, 2009As of December 28, 2009, worldwide more than 208 countries and overseas territories or communities have reported laboratory confirmed cases of pandemic influenza H1N1 2009, including at least 13,000 deaths Northern Hemisphere: Overall disease activity has recently peaked.Central and Eastern Europe, and in parts of West, Central, and South Asia: Continued increases in influenza activity United States and Canada: Influenza activity continues to be geographically widespread but overall levels of influenza-like-illness has declined substantially Approximately 53% of hospitalized cases in Canada had an underlying medical conditionEurope: Widespread and active transmission continued to be observed throughout the continentOverall pandemic influenza activity appears to have recently peaked across a majority of countriesWestern and Central Asia: Virus circulation remains active throughout the region, however disease trends remain variableEast Asia: Influenza transmission remains active but appears to be declining overallCentral and South America and the Caribbean: influenza transmission remains geographically widespread but overall disease activity has been declining or remains unchanged in most parts, except for in Barbados and Ecuador, were recent increases in respiratory diseases activity have been reportedSouthern Hemisphere: Sporadic cases of pandemic influenza continued to be reported without evidence of sustained community transmission.

SummaryIn the US Highest incidence of lab-confirmed cases reported among 5-24 years oldHighest hospitalization rate among 0-4 years oldUnderlying health conditions confers high risk of complications and deathsIn MexicoMajority of the cases reported in health young adults70% of the deaths were reported in healthy young adults, 20-54 years Individuals 60+ seem to be protected as the number of cases and have a lower case-fatality compared to the rest of the populationIn EUMajority of the cases reported in health young adults (20-29 years)GloballyNumber of deaths being reported is risingVaccine Total Adverse Events: 5.4% (0.3% fatal)Sanofi Pasteur & MedImmune vaccine recalled due to potency issuesAnti-virals (oseltamivir and zanamivir)Oseltamivir resistance reported recently in immunocompromised patents

Conclusion/RecommendationsPast experience with pandemics have taught us that the second wave is worse than the first causing more deaths due to:Primary viral pneumonia, Acute Respiratory Distress Syndrome (ARDS), & Secondary bacterial infections, particularly pneumoniaFortunately compared to the past now we have vaccines, anti-virals and antibiotics (to treat secondary bacterial infections) & rT-PCR based rapid diagnostic devicesThis pandemic is milder than previously predicted with a case-fatality less than 1%

At present most of the deaths due to the novel H1N1 strain has been reported from the Americas. Disease seems to be affecting the healthy strata of the population based upon epidemiological dataAnecdotal data suggests that the number of deaths among the pediatric population has risen recently due to infection with the novel H1N1Most of these deaths however have been reported in cases with underlying medical conditions60 years and above age group seems to show some protection against this strain suggesting past exposure and some immunity

Conclusion/RecommendationsEach locality/jurisdiction needs to Have enhanced disease and virological surveillance capabilitiesDevelop a plan to house large number of severely sick and provide care if needed to deal with mildly sick at home (voluntary quarantine) Healthcare facilities/hospitals need to focus on increasing surge capacity and stringent infection prevention/controlGeneral population needs to follow basic precautions

In the Northern Hemisphere influenza viral transmission traditionally stops by the beginning of May but in pandemic years (1957) sporadic outbreaks occurred during summer among young adultsThis novel H1N1 strain has survived high humidity or temperature and continued to spread during the summer months and will continue to spread and cause infection

Conclusion/RecommendationsSchool Closures:Preemptive school closures merely delay the spread of disease Once schools reopen the disease transmits and spreads Puts unbearable pressure on single-working parents and would be devastating to the economy Closure after identification of a large cluster would be appropriate as absenteeism rate among students and teachers would be high enough to justify this action

Burden of Disease & MortalityActual burden of the disease will be higher than the regular seasonal flu despite the availability of vaccine, antivirals and excellent public knowledge With the variation in reporting it is very difficult to appreciate the total number of deaths

It is imperative to appreciate that times-have-changed Though this strain has spread very quickly across the globe and seems to be highly infectious, today we are much better prepared than 1918 There is better surveillance, communication, understanding of infection control, vaccines, anti-virals, antibiotics and advancement in science and resources to produce countermeasures quickly

References World Health Organization (WHO):http://www.who.int/csr/disease/avian_influenza/en/ World Organization for Animal Health (OIE): http://www.oie.int/wahid-prod/public.php? Centers for Disease Control & Prevention (CDC): http://www.cdc.gov/flu/avian/index.htmChotani R. Just-in-time, H1N1 Influenza. Epidemiology Supercourse. December 2009.El-Bushra H. Global and Regional Update on Human Pandemic Influenza A H1N1 2009. Cairo: WHO/EMRO, 2009

**This lecture provides basic information on Swine Flu. The lecture is updated to include the latest information and data.*The internal antigens (M1 and NP proteins) are the type-specific proteins (type-specific antigens) used to determine if a particular virus is A, B or C. The M1 proteins of all members of each type show cross reactivity. The NP proteins of all members of each type also show cross reactivity.The external antigens (HA and NA) show more variation and are the subtype and strain-specific antigens. These are used to determine the particular strain of influenza A responsible for an outbreakFlu strains are named after their types of hemagglutinin and neuraminidase surface proteins, so they will be called, for example, H3N2 for type-3 hemagglutinin and type-2 neuraminidase. If two different strains of influenza infect the same cell simultaneously, their protein capsids and lipid envelopes are removed, exposing their RNA, which is then transcribed to mRNA. The host cell then forms new viruses that combine antigens; for example, H3N2 and H5N1 can form H5N2 this way. Because the human immune system has difficulty recognizing the new influenza strain, it may be highly dangerous.

*A cytokine storm is the systemic expression of a healthy and vigorous immune system resulting in the release of more than 150 inflammatory mediators (cytokines, oxygen free radicals, and coagulation factors). Both pro-inflammatory cytokines (such as Tumor Necrosis Factor-alpha, InterLeukin-1, and InterLeukin-6) and anti-inflammatory cytokines (such as interleukin 10, and interleukin 1 receptor antagonist) are elevated in the serum, and the fierce and often lethal interplay of these cytokines is referred to as a "Cytokine Storm". The primary contributors to the cytokine storm are TNF-a (Tumor Necrosis Factor-alpha) and IL-6 (Interleukin-6). The cytokine storm is an inappropriate (exaggerated) immune response that is caused by rapidly proliferating and highly activated T-cells or natural killer (NK) cells. These cells are themselves activated by infected macrophages. The cytokine storm must be treated and suppressed or lethality can result. *Reassortment, or Viral Subunit Reassortment, is the exchange of DNA between viruses inside a host cell. Two or more viruses of different strains (but usually the same species) infect a single cell and pool their genetic material creating numerous genetically diverse progeny viruses. It is a type of genetic recombination.Reassortment can lead to a viral shifts under some conditions.

*WHO Definition of Phases Phase 4 is characterized by verified human-to-human transmission of an animal or human-animal influenza reassortant virus able to cause community-level outbreaks. The ability to cause sustained disease outbreaks in a community marks a significant upwards shift in the risk for a pandemic. Any country that suspects or has verified such an event should urgently consult with WHO so that the situation can be jointly assessed and a decision made by the affected country if implementation of a rapid pandemic containment operation is warranted. Phase 4 indicates a significant increase in risk of a pandemic but does not necessarily mean that a pandemic is a forgone conclusion. Phase 5 is characterized by human-to-human spread of the virus into at least two countries in one WHO region. While most countries will not be affected at this stage, the declaration of Phase 5 is a strong signal that a pandemic is imminent and that the time to finalize the organization, communication, and implementation of the planned mitigation measures is short. Phase 6, the pandemic phase, is characterized by community level outbreaks in at least one other country in a different WHO region in addition to the criteria defined in Phase 5. Designation of this phase will indicate that a global pandemic is under way.During the post-peak period, pandemic disease levels in most countries with adequate surveillance will have dropped below peak observed levels. The post-peak period signifies that pandemic activity appears to be decreasing; however, it is uncertain if additional waves will occur and countries will need to be prepared for a second wave. Previous pandemics have been characterized by waves of activity spread over months. Once the level of disease activity drops, a critical communications task will be to balance this information with the possibility of another wave. Pandemic waves can be separated by months and an immediate at-ease signal may be premature. In the post-pandemic period, influenza disease activity will have returned to levels normally seen for seasonal influenza. It is expected that the pandemic virus will behave as a seasonal influenza A virus. At this stage, it is important to maintain surveillance and update pandemic preparedness and response plans accordingly. An intensive phase of recovery and evaluation may be required.

*World Health Organization**World Health Organization**For planning purposes there are these four components of a pandemic wave Initiation, Acceleration, Peak and Decline. The percentage on the vertical axis represents the proportion of all those infected in the first wave that are infected in the different phases After the decline there may be a second and even a third wave before influenza settles back down to its seasonal pattern again. The seasonal flu is usually worse than the years before the pandemic because the seasonal flu is invigorated with new genetic material. The same four phases actually apply to epidemics as well. This particular wave has been given an erratic Initiation Phase representing what is happening in Europe in the summer and perhaps early Autumn when there are small outbreaks and it is not clear when each country will enter their Acceleration Phase. However, no pandemic has ever behaved in quite so neat a way as shown here. Pandemics dont follow set patterns and each is different. It is also important that this is a national curve. The local curves are more narrow and with a higher central peak, i.e. local pandemic spread is shorter and sharper but also highly variable.This slide the original of which was developed by the United States CDC illustrates the theoretical aims of community mitigation by public health measures, mass use of antivirals etc. However it needs to be appreciated that the effectiveness of PHM is by no means certain. A further discussion of this can be found through the ECDC PHM Menu http://ecdc.europa.eu/en/Health_Topics/Pandemic_Influenza/phm.aspx

1 - Serologic testing on paired acute- (within 1 week of illness onset) and convalescent-phase (collected 2-3 weeks later) sera is limited to epidemiological and research studies, is not routinely available through clinical laboratories, and should not inform clinical decisions. 2 - The amount of time needed from specimen collection until results are available. 3 - Compared with rRT-PCR tests; rRT-PCR tests are compared to other testing modalities including other rRT-PCR assays. 4 - Rapid Influenza Diagnostic Tests include tests that are CLIA waived (can be performed in an outpatient setting) and tests that are moderately complex (can be performed only in a laboratory). Clinical specimens approved for RIDTs vary by test, and may not include all respiratory specimens. 5 - Performance of these assays relies heavily on laboratory expertise and requires a fluorescent microscope 6 - Requires additional testing on the viral isolate 7 - The performance of rRT-PCR assays specific for 2009 H1N1 influenza have not been established for bronchoalveolar lavage and tracheal aspirates. If testing these specimens for 2009 H1N1 influenza consider testing in parallel with a nasopharyngeal, nasal, or oropharyngeal swabs or a nasal aspirate. 8 - See discussion on available rRT-PCR assays at http://www.cdc.gov/h1n1flu/guidance/diagnostic_tests.htmPregnant WomenOseltamivir and zanamivir are "Pregnancy Category C" medications, indicating that no clinical studies have been conducted to assess the safety of these medications for pregnant women. Because of the unknown effects of influenza antiviral drugs on pregnant women and their fetuses, oseltamivir or zanamivir should be used during pregnancy only if the potential benefit justifies the potential risk to the embryo or fetus; the manufacturers' package inserts should be consulted. However, no adverse effects have been reported among women who received oseltamivir or zanamivir during pregnancy or among infants born to women who have received oseltamivir or zanamivir. Pregnancy should not be considered a contraindication to oseltamivir or zanamivir use. Because of its systemic activity, oseltamivir is preferred for treatment of pregnant women. The drug of choice for prophylaxis is less clear. Zanamivir may be preferable because of its limited systemic absorption; however, respiratory complications that may be associated with zanamivir because of its inhaled route of administration need to be considered, especially in women at risk for respiratory problems.Adverse Events: http://www.cdc.gov/flu/professionals/antivirals/side-effects.htmStaff should be medically cleared, fit-tested, and trained for respirator use, including: proper fit-testing and use of respirators, safe removal and disposal, and medical contraindications to respirator use. Information on respiratory protection programs and fit test procedures can be accessed at www.osha.gov/SLTC/etools/respiratory

More information can be found at http://www.cdc.gov/ncidod/dhqp/gl_environinfection.html

Please send questions or comments to Dr. Chotani at chotani@gmail.comPlease send questions or comments to Dr. Chotani at chotani@gmail.com