What is an influenza pandemic?

• A global epidemic of influenza resulting from a combination of

– the emergence of an influenza A virus with a sub-type different from strains circulating among humans in recent years

– a high proportion of susceptible people in the community

– high person-to-person transmissibility of the new virus, with accompanying human disease

Re-assortment and Direct TransmissionRe-assortment and Direct Transmission

HumanHuman virusvirus

ReassortantReassortantvirusvirus

Non-humanNon-humanvirusvirus

Global situation as of 18:00 GMT, 13th May 2009

• 33 countries have officially reported 6,302 cases of influenza A (H1N1) infection.

• Mexico has reported 2,282 laboratory confirmed human cases of infection, including 58 deaths.

• The United States has reported 3,352 laboratory confirmed human cases, including three deaths.

• Canada has reported 353 laboratory cases, one death.

• Costa Rica has reported 8 laboratory cases, one death.

The following countries have reportedlaboratory confirmed cases with no deaths:

Argentina (1) Australia (1)Austria (1) Brazil (8)China mainland and Hong Kong SAR (4)Colombia (7) Cuba (1)Denmark (1) El Salvador (4)Finland (2) France (14)Germany (12) Guatemala (3)Ireland (1) Israel (7) Italy (9) Japan (4)Netherlands (3) New Zealand

(7)Norway (2) Panama (29)Poland (1) Portugal (1)

Republic of Korea (3) Spain (100)Sweden (2) Switzerland (1) Thailand (2) UK (71)

How has the situation evolved?From present day…

• 13 May, Africa is the only unaffected continent. Cases exceed 6000, with the highest number being in US (3352), Mexico (2282), Canada (353) Spain (100) and UK (71).

• 11 May, a new death is reported in Costa Rica, where there are 8 confirmed cases

• 9 May, by now, 29 countries have reported case with deaths occuring in Mexico, USA and Canada.

• 5 May, continued increase in cases reported by country, although WHO does not

believe it is seeing community transmission elsewhere outside the PAHO region.

• 3 May, WHO will release its stockpile of oseltamivir to 72 developing countries and Mexico.

• 30 April, confirmed figures continue to change rapidly. USA also reports a death, hospitalized patients. WHO moves to phase 5.

• 27 April, Mexico government announced closure of schools across the country. Spain and the United Kingdom confirmed first cases. WHO moves to phase 4.

How has the situation evolved? 26 April, Mexican government closed schools, some public places

in Mexico city. Canada confirmed first cases.

By 25 April, Mexico government reported 1149 persons (71 deaths, CFR 6.2%) occurring from 17-24 April under investigation for severe respiratory disease. Mexican government issued health advisory, closed some public places (schools, libraries, museums, theatres), distributed surgical masks. WHO declares a public health emergency of international concern (PHEIC).

• Evening of 24 April, it was reported that 18 out of 51 specimens from Mexico sent for laboratory confirmation in Canada tested positive for H1N1 and 12 were identical to the strain confirmed in US

• Early morning of 24 April, US confirmed 7 cases (5 California, 2 Texas).

• 23 April, Mexico alerted WHO in the middle of the night of a sudden high number of cases and deaths from a severe respiratory disease. WHO activated their SHOC room.

• End March – April 09: Unusual 'end of season' influenza activity was observed in Mexico.

…to genesis

Phase 1 No animal influenza virus circulating among animals has been reported to cause infectionin humans.

Phase 2 An animal influenza virus circulating in domesticated or wild animals is known to havecaused infection in humans and is therefore considered a specific potential pandemicthreat.

Phase 3 An animal or human-animal influenza reassortant virus has caused sporadic cases orsmall clusters of disease in people, but has not resulted in human-to-human transmissionsufficient to sustain community-level outbreaks.

Phase 4 Human-to-human transmission (H2H) of an animal or human-animal influenza reassortantvirus able to sustain community-level outbreaks has been verified.

Phase 5 The same identified virus has caused sustained community level outbreaks in two or morecountries in one WHO region.

Phase 6 In addition to the criteria defined in Phase 5, the same virus has caused sustainedcommunity level outbreaks in at least one other country in another WHO region.

Post-peak period

Levels of pandemic influenza in most countries with adequate surveillance have droppedbelow peak levels.

Possible new wave

Level of pandemic influenza activity in most countries with adequate surveillance risingagain.

Post-pandemic period

Levels of influenza activity have returned to the levels seen for seasonal influenza in mostcountries with adequate surveillance.

WHO PANDEMIC PREPAREDNESS AND RESPONSE GUIDANCE 2009: PHASES

Phase 5 changes• Phase 5 is characterized by human-to-

human spread of the virus into at least two countries in one WHO region.

• 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.

• All countries should immediately activate pandemic preparedness plans.

Phase 5 changes

• Effective and essential measures include heightened surveillance, early detection and treatment of cases, and infection control in all health facilities.

• The criteria to move to phase 6 (pandemic) would be triggered by sustained community in a second WHO region, where there is clear evidence of community-level transmission outside the Americas

An influenza pandemic is a global event thatcalls for global solidarity.

What is important to monitor• Spread of epidemic,

• Severity of illness (case fatality rate)

• Community outbreaks

• further international spread of the virus,

and further spread in countries that are

already reporting cases.

• Historically, influenza pandemics have encircled the globe in two, sometimes three, waves. The present situation can change because influenza viruses are constantly changing in unpredictable ways.

Why not rapid containment?

• WHO has a containment protocol

• Containment = efforts to stop the pandemic

• Mitigation = efforts to minimize illness/death (and slow down transmission to buy time for better preparedness and

vaccine development/production)

• Protocol includes criteria for decision-making

• This situation does not meet criteria for attempting containment (based on available evidence)– too widespread already

– Unfeasible to operationalize

So, what to do?• Countries should focus efforts more on mitigation

rather than containment

• Actions to ensure safety of people

• Ensure clear messages and transparent communications

• Social and personal protection (social distancing, hand hygiene, cough etiquette)

Refrain from introducing measures that are economicallyand socially disruptive, yet have no scientific justificationand bring no clear public health benefit - all the moreimportant at a time of economic downturn.

Main Actions for Phase 5

Phase 5:The virus has caused

sustained community level outbreaks in two or more

countries in oneWHO Region.

Increase surveillance

Implement individual & community precaution

measures

Considerswitching topandemic

vaccine

Continue communication

& updates

Activate contingency

plan for Health care

Activate multi-sector

coordination

Travel related measuresissued by WHO as temporary recommendations under IHR:

Not to close borders and not to restrict international travel

and

The relevant provisions in the IHR with respect to such measures and the need to inform WHO and provide the public health rationale and relevant scientific information for measures that significantly interfere with international traffic

– At this point FOCUS should be on safety of people– Closing borders or restricting travel WILL NOT slow virus spread

much– Previous experiences (SARS) have shown that closure of points of

entry is very effective in disrupting the economy but not virus transmission!

However…

• It is prudent for people who are ill to delay international travel

• Returning travelers who have become ill to seek medical attention in line with guidance from national authorities

These steps are prudent for all diseasesnot just influenza

Is it safe to eat pork?

Yes

• Influenza viruses are not known to be transmissible to people through eating processed pork or other food products derived from pigs.

• Heat treatments commonly used in cooking meat (e.g. 70°C/160°F coretemperature) will readily inactivate any virusespotentially present in raw meat products.

Treatment of cases

• Standard treatment as for previous guidelines

• Virus have shown sensitivity to:

OseltamivirZanamivir

Vaccine production• No vaccine currently available for this novel strain

• A multi-step process with many groups involved to develop a vaccine

• 4-6 months to develop a new vaccine and have the first batch of vaccine available; several months for mass production.

• WHO is working closely with its partners to make vaccine virus prototypes – the first steps

• Global manufacturing capacity, though greatly increased, is insufficient to produce enough antiviral medication and pandemic vaccines to protect the entire world population in time.

• Acquiring data to guide wise and targeted use of interventions, conserve supplies, and, in the case of antiviral medicines, reduce the risk of drug resistance.

• Influenza viruses tend to change constantly thus virus sharing critical to have as many strains as possible available to increase the likelihood of a protective vaccine.

What WHO is doing• Constant monitoring and risk assessment

• Providing support to Mexico through GOARN (Global Outbreak Alert and Response Network)

• Working with its network of laboratories to development laboratory reagents to test for this novel virus and the vaccine

Working with WHO Member States to enhance surveillance

Working with WHO Collaborating Centers for vaccine preparation

What WHO is doing• Providing written guidance to support Member

States:– Hospitals/Infection control– Surveillance– Laboratory

• Activating preparedness plans

• Communicating real time information/advice to the public, Member States, partners, etc.

• Ensuring 2-way communication

What can the public do?Prepare for social distancing (home supplies)

Practice good hand hygiene

Practice good cough etiquette

Listen for public health advisories (WHO,MOH) as the

situation is very fluid 

The risk is not hyping the pandemic threat, but undeplaying it. We know a tsunami is coming. No one can say whether it will be just a large wave, or a monsterous one, but it is time to start thinking about at least being ready to move to higher ground.

Nature, vol 459, issue no. 7243. 7 May 2009