Flu pandemic: focusing on the social response■ Background

Several pandemics ever occurred
Spanish flu 1918 (H1N1): 20-40 million deaths➔ Asian flu 1957 (H2N2)➔
Hong Kong flu 1968 (H3N2)➔ Russian flu 1977 (H1N1)➔

Newly introduced strains generally had high virulence Avian flu (H5N1) since 1997 had high virulence forbirds, and some human patients also suffered from it

Case Fatality Rate for human was more than 60%➔No human to human infection➔

WHO and CDC noticed the possibility of coming
pandemic by H5N1 when it would acquire infectivity
from human to human "International Health Regulations" were updated in2005 (activated since 15 June 2007)➔

http://www.who.int/ihr/en/

1

Contribution of mathematical models■ Containment of initial epidemic by ring-vaccination

Ring vaccination of residents around the initially imported cases
can prevent extensive transmission"WHO pandemic influenza draft protocol for rapid response andcontainment" (updated draft 30 May 2006)
Longini IM, et al. Science 309: 1083-1087, 2005
Ferguson NM, et al. Nature 437: 209-214, 2005
■ School closure as soon as possible after initial casedetection may contribute to suppression of epidemic

Based on realistic transmission parameter in French, simulation
model clarified its possibilityJapanese Government decided that all the school within aprefecture should be closed just after the initial case detection
Cauchemez S, Valleron AJ, Boëlle PY, Flahault A, Ferguson
NM. Estimating the impact of school closure on influenza
transmission from Sentinel data. Nature. 452:750-754, 2008.
■ The number of patients projected by CDC FluAid2.0(Meltzer, Cox, Fukuda 2000)

2Flu researchers■ Theoretical EpidemiologistsImperial College Group (UK) – followers of Anderson RM➔

Niel M Ferguson (who also suggested the necessity of behavioral followup)[http://www1.imperial.ac.uk/medicine/people/neil.ferguson/publications/]

Several Groups in USA➔

Ira M. Longini, University of Washington[http://www.biostat.washington.edu/sites/www/content/files/misc/longini_ira_490c90ca28.pdf]

Marc Lipsitch, Harvard University[http://www.hsph.harvard.edu/faculty/marc-lipsitch/]➔ Carlos Castillo-Chavez, Arizona State Univ.
[https://webapp4.asu.edu/directory/person/566521]➔

Germany (Klaus Dietz), Netherlands (Odo Diekmann,J.A.P. Heesterbeek, Hiroshi Nishiura), Japan (YasushiOhkusa, etc.)■ Virologists / Medical zoologists
 Yoshihiro Kawaoka's group (Univ. Tokyo, Japan)
➔

Takeshi Noda et al. Nature 15 June 2009

Hiroshi Kida's group (Hokkaido Univ., Japan) Elodie Ghedin (Univ. Pittsburgh) Nancy J. Cox (CDC), Keiji Fukuda (WHO)3

Preparation by several countries
USA (http://www.pandemicflu.gov/index.html)
"Monitering Outbreaks" have undergone
100 million dollars were invested to vaccine study

FluAid2.0, FluSurge2.0, FluWorkLoss1.0 (CDC)■ UK
A national framework for responding to an influenza pandemic■ Canada
The Canadian Pandemic Influenza Plan for the Health Sector■ AustraliaAustralian Health Management Plan for PANDEMIC INFLUENZA■ NZ
New Zealand Influenza Pandemic Action Plan 2006
■ EU
EWRS; Early Warning and Response SystemHEDIS; Health Emergency and Disease Information System

MedISys; Medical Intelligence Sytem■ Japan (http://www.cas.go.jp/jp/influenza/index.html)
Cabinet Secretariat and Ministry of Health, Labor and WelfareTeam acting against novel influenza was made in MHLW since 2008
Law to prevent infectious diseases changed in 2007

Guideline for novel influenza was made on 17 Feb 20094■

WHO's response since 26 April 2009
■ http://www.who.int/csr/disease/swineflu/en/index.html

5Tracking Swine Flu (April 27, 2009 NYTimes)■■

United States officials declared apublic health emergency on Sunday(26 April) over increasing cases ofswine flu, but continued to urge
Americans not to panic on Monday, asmost of the cases have been mild.
Confirmed cases
■

As of Monday (27 April), officials had confirmed
42 cases of a new A(H1N1) swine flu virus in
the United States, including 28 New York City
high school students. Six cases were identified
in Canada — all linked to travel in Mexico.
While the World Health Organization says 20
swine flu cases in Mexico have been confirmed,
officials say there are at least 1,600 suspected
infections and at least 149 suspected deaths.
One infection was confirmed in eastern Spain.

■Swine flu and humans
Swine flu viruses can be passed between pigs
and humans, but human infections are notcommon. Most infections occur among people
with direct pig contact. Sometimes a flu virus
can mutate to be more transmissible tohumans. An outbreak occurred among soldiersin Fort Dix, N.J., in 1976, resulting in 200
infections, several serious illnesses and one
death.

Precautions
The Centers for Disease Control andPrevention recommends washing hands
frequently, avoiding touching the face, covering
the nose and mouth when sneezing and staying
home when sick. People cannot be infected byeating pork.

6

Global Response to Swine Flu (Source: NY Times)
■■

■
■

■
■
■

The global spread of swine flu, a contagious respiratory illness, has caused
governments to react. Homeland Security Secretary Janet Napolitano
declared a public health emergency on Sunday (26 April 2009) after
announcing that 20 cases had been confirmed in the United States.
Officials confirmed eight cases in New York, seven in California, two in
Kansas, and one in Ohio. About 100 students at St. Francis Preparatory
School in Fresh Meadows, Queens, became sick in the last few days. NewYork Mayor Michael R. Bloomberg said that all the cases had been mild.
Quarantine officers monitored travelers with a thermographic device at thearrival gate at Narita International Airport, which serves Tokyo.
Travelers with face masks at Mexico City's international airport. Because ofthe outbreak, events were canceled, and schools and museums were closed.
The swine flu has killed more than 80 people in Mexico and infected 1,300
more, reported the Associated Press.
A member of the Mexican army handed out face masks to tourists andpedestrians in Mexico City on Sunday (26 April 2009).
A priest talked with a group of nuns wearing masks as a preventive measurein front of the Basilica of Guadalupe in Mexico City.
Even Sunday Mass was affected. The Roman Catholic Church gave
worshipers the option to listen to services on the radio, and priests whodecided to hold services were told to be brief. Priests were also encouraged
to put Communion wafers in worshipers' hands instead of their mouths. At
the Basilica of Guadalupe, only two church workers attended Mass.
7A side effect – computer virus■ 29 April 2009: Fake CDC's alert e-mail with theattachment named “Swine influenza frequently asked
questions.pdf.” It contained a computer virus.
https://forums2.symantec.com/t5/blogs/blogarticlepage/blog-id/malicious_code/article-id/268■ In the end of April 2009: "Search Engine Optimization

Poisoning" is reported. When a user searched websites using "swine" as a search word, malware
containing sites was listed in top page.
IPA [http://www.ipa.go.jp/security/txt/2009/06outline.html]■ 30 April 2009: In Japan, virus containing e-mails werefound. It is pretended as sent by the National
Institute for Infectious Diseases, and the attached file
titled "Knowledge about swine flu " (actually inJapanese) included a computer virus.
Yomiuri Shimbun [http://www.yomiuri.co.jp/feature/20090425-436828/news/20090430-OYT1T00396.htm]

8

From "Swine flu" to "Influenza A(H1N1)"■ A/H1N1 influenza like human illness in Mexico and theUSA: OIE [World Organization for Animal Health]statement (Paris, April 27 2009)
It would be logical to call this disease “North-American influenza”[http://www.oie.int/eng/press/en_090427.htm]■ WHO stopped using "swine", by pork industry's requestIn addition, the Egyptian government, where the national religion is Islam, decided to kill all pigs raisedby minor Christians within the country to prevent publics from "swine flu" on 29 April 2009.

■ Joint FAO/WHO/OIE Statement on influenza A(H1N1) andthe safety of pork (May 7 2009; To avoid any
misunderstanding FAO, WHO and OIE would like toreissue their joint statement originally issued on 30 April)
In the ongoing spread of influenza A(H1N1), concerns about the possibility of this virus being found inpigs and the safety of pork and pork products have been raised.
Influenza viruses are not known to be transmissible to people through eating processed pork or other foodproducts derived from pigs.
Heat treatments commonly used in cooking meat (e.g. 70°C/160°F core temperature) will readily
inactivate any viruses potentially present in raw meat products.
Pork and pork products, handled in accordance with good hygienic practices recommended by the WHO ,Codex Alimentarius Commission and the OIE, will not be a source of infection
Authorities and consumers should ensure that meat from sick pigs or pigs found dead are not processed orused for human consumption under any circumstances.
[http://www.who.int/mediacentre/news/statements/2009/h1n1_20090430/en/index.html]
9Enserink M: Swine flu names evolving faster than swine flu itself. Science, 324(5929): 871, 15 May 2009■Academic responses■ Many scientific journals opened special sites, rushed!
Science [http://blogs.sciencemag.org/scienceinsider/swine-flu/]
Nature [http://www.nature.com/news/specials/swineflu/index.html]
NEJM [http://h1n1.nejm.org/]
Lancet [http://www.thelancet.com/H1N1-flu]

BioMed Central [http://www.biomedcentral.com/gateways/influenza]
Cohen J: Flu researchers train sights on novel tricks of novel H1N1. Science,
324(5929): 870. [http://www.sciencemag.org/cgi/content/full/324/5929/870]■ Health Education via Internet
Supercourse in the University of Pittsburgh[http://www.pitt.edu/~super1/lecture/lec34601/index.htm]➔ The latest information is given by the specialists and tranlated intoSpanish, Russian, Farsi, Arabic, Vietnamese, Bahasa Melayu (Malay),French, Macedonian, Chinese, Hebrew, Bosnian, and Japanese, which
are freely accessed via Internet➔

Peter M. Sandman's article as a risk communication

A short version was published as a commentary to Nature.
➔ [http://www.nature.com/nature/journal/v459/n7245/full/459322a.html]➔ Original long version is given as an online article[http://www.psandman.com/col/swineflu1.htm]➔ The Nature article is translated into French, which is also given online[http://www.zonegrippeaviaire.com/showthread.php?t=973#2]➔10

Some social impacts in Japan■ Masks sold outIn mid-May, face masks disappeared. Net auction price wasraised up to 10 times higher than original.

■ School closure

Hyogo and Osaka prefectures closed all schools for 1 week(though the closure is decided by the principal, it wasrequested by the government).

Several Universities in Kansai area closed for 5-7 days, but
Kyoto University didn't.
■ Many events were suspended or prolonged.
■ Emergency medicine delayed due to intensive

setting of "Special department for fever outpatient"■ Patients were refused to treat in some hospitals(Japan's Minister of Health, Labor and Welfare
MASUZOE critisized it but not efficiently assisted.)11

Japanese Newspapers opened special-site.
■ THE KOBE SHIMBUN■ Yomiuri Shimbun

http://www.yomiuri.co.jp/feature/20090425-436828/index.htm(16 May 2009, First Japan's[1] 24 April 2009: US Swine? flu 7 patients, possible human tohuman infection (only 1 article)
confirmed patients found in[2] 25 April 2009: Suspected 60 deaths by swine origin flu tohuman in Mexico and other countries [+8 articles]
Kobe, the newspaper was[3] 26 April 2009: WHO's alert of public health, but declarationof phase 4 was prolonged [+11 articles]
filled up by Influenza[4] 27 April 2009: Matsuya stopped to sell "Ton-teki set" (incl.
Mexican pork) [+15 articles]
information, 30 topics given)[5] 28 April 2009: WHO declared phase 4 [+33 articles]29 April 2009: Egyptian government decided to kill all pigs
Reported information on the [6][+18 articles][7] 30 April 2009: WHO declared phase 5 [+22 articles]
case fatality/severity was[8] 1 May – 7 May [114 articles][9] 8 May – 14 May [103 articles]
only based on Mexico/USA[10] 15 May – 21 May [123 articles] incl. 16 May[11] 22 May – 28 May [48 articles]data.
[12] 29 May – 4 June [30 articles] 3 June "It's ease" by Hyogo[13] 5 June – 11 June [26 articles]
In Hyogo prefecture (incl.
[14] 12 June – 18 June [20 articles] WHO phase 6 on 12 June[15] 19 June – 24 June [15 articles]
Kobe city), all schools were
■ Mainichi Shimbun
closed for 1 week. Manyhttp://mainichi.jp/select/science/swineinfluenza/students went to Karaoke,■ Asahi Shimbun
but were denied to enter.
http://www.asahi.com/health/pandemicflu/

Initial epidemic among highNumbers of articles wereschool students were notpeaked around the finding
reported in detail (due toethical reason).
1st patient in Japan
2

1

"Pandemic" (June 12 2009, NY Times)■ The announcement (of phase 6 "pandemic")does not mean that the illness, which has been
mild in most people, has become any worse.
The term pandemic reflects only thegeographic spread of a new disease, not its
severity. Pandemics typically infect about athird of the world in a year or two, andsometimes strike in successive waves.
■ The government of Hong Kong on Thursday(11 June) ordered all primary schools in thecity to be closed for two weeks after the firstcluster of local swine flu cases was found.
Above (right), kindergarten students at a local
school on Thursday (11 June).

13Current strategy in Japan
1. Basic Framework since 19 June 2009 (MHLW)[World situation]
Patients are still increasing, especially inthe Southern hemisphere●On 12 June, WHO declared "phase 6"●WHO requests for the countries, (1)continuous attention, (2) flexible response
to avoid socio-economical confusion●[Basic Concept]- nationwide strategy in fall/winter* From the viewpoint of that there may
be large increase of the number ofpatients, the destination is followings(1) Rapid and large increase should be
suppressed and/or delayed, to minimize
the effect of this disease on social activity
and medical supply[Future projection in Japan]
Stopping influx of patients from overseas
is impossible and incidence will continue●Some sporadic cases whose transmission
pathway cannot be specified occur, it is notstrange that national large-scale increase ofpatients may occur in coming fall/winter●Severe cases may increase among thepatients who have underlying diseases,
who must be appropriately treated●(2) Minimize the disease burden on the
medical facilities to supply appropriate
medical treatment for the severe cases(3) Not to count each occurrence ofinfection, but to capture the clue of large
increase of patients cluster(4) Set now as preparatory period, toavoid social confusion in fall/winter14

Patients Distribution in Japan (23 June)■ Number of patients by prefecture in 23 June 2009

More than 100 only in Hyogo and Osaka
50-99 in Tokyo, Chiba, Kanagawa and Fukuoka

1-49 patients found in 29 prefecturesNo patient found in 12 prefectures■ Severity in JapanNo severe cases were reported for these 881 patients.
If real rate of case severity was p, setting type 2 error of severecase detection as 0.2, upper limit of p was:1-0.2^(1/881)=0.0018
(additional comments on 16 July 2009) No severe case foundamong more than 3000 patients in Japan.
Hence upper limit of p is 0.00054 (However, of course, this value
ignore the age distribution and high risk group proportion in thepatients)■ Problems and riddle

Do confirmed cases truly reflect occurrence?
Why does severity differ in American Continents from elsewhere?
15

Number of patients by country (22 June 2009)
Source: WHO web site

2 deaths in Australia (age 26 and 37 males with underlying disease)■ 1 death in Phillipine (age 49 female with CVD)
16
■ All other deaths in North/South Americas■