Bioter­ror­ism only beaten by prepa­ra­tion and un­der­stand­ing

The Weekend Australian - Travel - - Health - PETER CUR­SON

IT is 30 years since the world saw the last case of small­pox, the last nat­u­ral case oc­cur­ring in So­ma­lia in 1977. The erad­i­ca­tion of small­pox rep­re­sents one of the great tri­umphs of pre­ven­ta­tive medicine and in­ter­na­tional co-op­er­a­tion in recorded his­tory.

Wiping out small­pox broke one of his­tory’s long­est chains of dis­ease trans­mis­sion, stretch­ing back more than 3000 years. In the 20th cen­tury, small­pox caused be­tween 300 and 550 mil­lion deaths, three times the num­ber in all wars dur­ing the cen­tury.

The feat of con­quer­ing the dis­ease was based on wide­spread vac­ci­na­tion sup­ported by ac­tive sur­veil­lance schemes, and that suc­cess raised the profile of pub­lic health. It ush­ered in a pe­riod of ac­tive pub­lic health cam­paigns aimed at a variety of in­fec­tious dis­eases.

Aus­tralia has been no stranger to small­pox, and the dis­ease was a fre­quent vis­i­tor to our shores un­til the early part of last cen­tury. The epi­demic that raged among the Abo­rig­i­nal pop­u­la­tion in 1789 and sur­faced reg­u­larly un­til the late 1860s re­mains prob­a­bly the only ex­am­ple of a ma­jor de­mo­graphic cri­sis in Aus­tralia’s his­tory. The last ma­jor out­break of small­pox oc­curred in NSW in 1913-17, when more than 3000 peo­ple caught the dis­ease.

What rel­e­vance does small­pox hold for us to­day? For the gen­er­a­tions born since vac­ci­na­tion, it re­mains a dis­tant me­mory as­so­ci­ated with par­ents or grand­par­ents. For those of us vac­ci­nated in the past there is the be­lief (un­true as it turns out) that we had been granted a life­long im­mu­nity to the dis­ease.

Small­pox, along with other bi­o­log­i­cal agents, is once again in the spot­light due to con­cern about the pos­si­bil­ity that an il­lic­itly ob­tained sup­ply of the virus could be de­lib­er­ately re­leased.

In 2004 the Aus­tralian Gov­ern­ment pro­duced a man­age­ment/re­sponse plan for just such an event, and while bird flu and the threat of a pan­demic of in­fluenza have pushed bioter­ror­ist events into the back­ground, the threat re­mains. A sur­vey of 1001 Aus­tralians in 2004 in­di­cated that more than half thought that a bioter­ror­ist event in Aus­tralia was of medium to high con­cern, and of those not pre­vi­ously vac­ci­nated against small­pox many ex­pressed a strong will­ing­ness to ac­cept vac­ci­na­tion as a pre­cau­tion­ary mea­sure in the ab­sence of a bioter­ror­ist event.

No one re­ally knows what be­came of the tens of tonnes of mod­i­fied small­pox virus that was part of the Soviet bi­o­log­i­cal war­fare pro­gram up un­til the early 1990s, or what be­came of many of the thou­sands of sci­en­tists work­ing on this pro­gram. Other na­tions are thought to have se­cret stocks of the virus.

The sarin re­lease by a Ja­panese cult in 1995 and the an­thrax in­ci­dent in the US some years later in­di­cate the ease of ob­tain­ing, mod­i­fy­ing and re­leas­ing bi­o­log­i­cal agents into un­sus­pect­ing pop­u­la­tions. But we should not ex­ag­ger­ate this threat. ‘‘ Rogue’’ states or bioter­ror­ists seek­ing to ac­quire and use small­pox as a weapon would have to over­come some fairly sig­nif­i­cant ob­sta­cles.

Th­ese would in­clude the need to grow the virus in eggs or hu­man tis­sue, and find­ing an ef­fec­tive way to dis­perse the virus into a vul­ner­a­ble pop­u­la­tion. But in the un­likely event of such a bioter­ror­ist re­lease of small­pox in Aus­tralia, how well are we pre­pared?

The back­bone of pre­pared­ness is an ex­cel­lent sys­tem of sur­veil­lance and re­sponse in­volv­ing the ready avail­abil­ity of an ac­ces­si­ble and safe vac­cine, and a health­care and emer­gency sys­tem that can re­spond in a timely man­ner.

Prob­a­bly Aus­tralia would need be­tween 2 and 5 mil­lion doses of vac­cine to feel safe. Cur­rently we hold be­tween 500,000 and 1 mil­lion doses of the old live virus. But re­gard­less of how many doses we cur­rently hold, who would we de­liver it to, where and how? Th­ese are im­por­tant ques­tions.

Given a sin­gle or clus­ter of small­pox cases, the timely de­liv­ery of vac­cine be­comes a pri­or­ity. Also, given the wave of pub­lic re­ac­tion, fear and hys­te­ria that we might ex­pect to re­sult, would not the pub­lic over­whelm the vac­ci­na­tion de­pots set up and would not the ‘‘ wor­ried well’’ over­run lo­cal GP prac­tices? This cer­tainly hap­pened in the past, and sim­u­la­tion ex­er­cises in the US sug­gest that it could hap­pen again.

How would we man­age this hu­man re­ac­tion? To do so we need to en­ter the frame of ref­er­ence of the av­er­age cit­i­zen and un­der­stand how they see risk and how this dif­fers from how ex­perts see risk. And who could we ex­pect to be vac­ci­nated? Key med­i­cal and emer­gency work­ers cer­tainly, but who else? The cur­rent man­age­ment plan sug­gests a ‘‘ ring fenc­ing’’ cam­paign, where cases and im­me­di­ate con­tacts would be vac­ci­nated. But given that small­pox has an in­cu­ba­tion pe­riod of up to 17 days, and that peo­ple move around a lot, how easy would trac­ing con­tacts prove?

And what about the im­pact on our health­care fa­cil­i­ties? Again the man­age­ment plan dis­cusses es­tab­lish­ing ‘‘ care cen­tres’’ — quar­an­tine hos­pi­tals? — which would be es­tab­lished in key lo­ca­tions. There seems lit­tle doubt, how­ever, that ex­ist­ing health­care fa­cil­i­ties would be pressed to the limit.

Hope­fully, a bioter­ror­ist event will never hap­pen in Aus­tralia, but if ever it does, we need to be as­sured that we are prop­erly pre­pared and fully un­der­stand all the is­sues. Peter Cur­son is ad­junct pro­fes­sor in the Cen­tre for In­ter­na­tional Se­cu­rity Stud­ies at the Univer­sity of Syd­ney and emer­i­tus pro­fes­sor in Med­i­cal Ge­og­ra­phy at Mac­quarie Univer­sity.

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