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Online Discussion: Tracking new emerging diseases and the next pandemic

Potential Smallpox Threat Theory

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Technophobe View Drop Down
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    Posted: March 15 2018 at 4:30pm

Weaponised smallpox virus could infect thousands in major cities

15 March 2018 • 11:39am

A weaponised smallpox virus could have a devastating effect on the world's major cities, infecting thousands because of the growing numbers of people with suppressed immunity, researchers have warned.

Smallpox, which was eradicated globally in 1980, is classed by the United States government as a category A bioterrorism agent because of its potential to spread rapidly, infect swathes of the population and incite widespread fear and panic.

Researchers at the University of South Wales have used a mathematical model to predict how many people would become infected and how many would die in bioterrorism attacks on New York and Sydney.

The data is likely to be scrutinised carefully by public health officials in Britain in the wake of the attack on Salisbury last week. Russia is known to hold samples of the smallpox virus. 

Raina MacIntyre, professor of infectious diseases epidemiology and lead author of the study, said that since smallpox was wiped out, the population has changed greatly with many more people living with conditions that suppress their immunity.  They would be particularly at risk of catching and therefore spreading the disease, she said.

"The change in medical immunosuppression since 1980, when smallpox was eradicated, is huge. Diseases like HIV were virtually unknown at the time.  The first heart-lung transplant had not yet occurred – transplantation medicine has progressed in leaps and bounds.

"We also have an ageing population, with age-related decline in immunity, and many more drugs for the treatment of cancer and autoimmune diseases which suppress immunity. No other model of smallpox has accounted for this," said Professor MacIntyre. 

The researchers estimated that about one in five people in New York and one in six in Sydney have lowered immunity but say these are probably conservative estimates.

Large-scale smallpox vaccination programmes ended in the 1970s meaning that there is also very little immunity in the general population.

The researchers put in place a scenario based on the smallpox virus being released in a crowded place, such as an airport, and then worked out how it would spread and its effect on the population over 100 days.

They calculated that an outbreak would peak at 70 days after the first case, by which time it would have infected around 4,200 people in New York, killing around 1,200. In Sydney, around 2,200 people would be infected, with more than 600 deaths.

Professor MacIntyre said that high levels of immunosuppression have not been considered in planning for smallpox attacks, with emergency planning still "rooted in the past".

She added that the implications for London would be the same as for New York and Sydney, as it has a similar number of immunosuppressed individuals - about 17 to 20 per cent of the population. 

"Large cities are at the greatest risk because of high population density, rapid spread of infection and greater difficulty in contact tracing of exposed people," she said. 

She urged authorities to start thinking about which vaccines could be used on which populations and how fast an outbreak could spread, given the high numbers of people with suppressed immune systems.

Commenting on the research, Amesh Adjala, an infectious diseases expert and senior scholar at the Johns Hopkins Center for Global Health Security, said the prospect of smallpox attack would be a “national security event without precedent”.

“It’s considered a major threat. The virus has been eradicated from the planet and only exists in designated repositories in the United States and Russia. It’s something people have thought about as a bioterrorism agent and that’s why the US government has put in so much effort to develop new vaccines,” he said.

Authorities would most likely tackle a smallpox epidemic with a technique called ring vaccination, where the contacts of those infected are vaccinated to form a ring protecting the rest of the population, said Dr Adjala.

However, he added that people with lowered immune systems would not be able to have the standard vaccine.

“With smallpox there has been an effort to develop new generation vaccines that are safe to use in the immuno-suppressed population. In the US they’re not yet licensed to use however they are stockpiled in the strategic national stockpile. In the event of an outbreak they would probably be given an emergency use authorisation,” he said.

The World Health Organization has stockpiled around 30 million doses of first, second and third generation vaccines.


Source   https://www.telegraph.co.uk/news/2018/03/15/weaponised-smallpox-virus-could-infect-thousands-major-cities/

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Post Options Post Options   Thanks (0) Thanks(0)   Quote CRS, DrPH Quote  Post ReplyReply Direct Link To This Post Posted: March 17 2018 at 12:58pm
^ Another good post!  Thanks, Techno! 

The Soviets had tons (metric tons) of freeze-dried smallpox, which they planned to load onto ICBMs in case of an attack on the US and NATO.  Much of this material has gone missing.  

North Korea is presumed to have smallpox weapons available, and other nations may as well.  

Only good thing is that there is a decent vaccine against smallpox, but as the article says, the population is aging and we have many more with compromised immune systems. 

Bad stuff. 
CRS, DrPH
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