Reading the Post-apocalypse

Post-apocalyptic fiction is all the rage these days. Before the Divergent series, The Hunger Games and The Road by Cormac McCarthy and even before Orwell's 1984, there was The Scarlet Plague (1912). Michele Augusto Riva and colleagues have just published a wonderful review of post-apocalyptic (post-plague) fiction in the October EID. Specifically, the authors focus on the literary history of pandemic infectious diseases from the Bible and Thucydides' History of the Peloponnesian War to Mary Shelley's Last Man (1826) and Jack London's The Scarlet Plague.

The Scarlet Plague takes place in 2073 after a 2013 "Red Death" pandemic that depopulated the earth in 2013. The novel tells "how the pandemic spread in the world and about the reactions of the people to contagion and death." Initially, people were convinced that scientists would be able to treat the bacteria (public trust in science was apparently high in London's version of 2013) but quickly the bacteria spread killing all within hours. Both London's novel and Riva's review are worth reading. There are many insights to be gained by looking at past responses to outbreaks (2009 H1N1, SARS) and fictional responses, as in London's novel, as we face current and future threats like Ebola, MERS and avian influenza.

Seasonal Flu Vaccine and Pandemic Severity: ICAAC 2012

Talk and discussion from Dr. Danuta Skowronski, BC Center for Disease Control, Vancouver, BC, Canada. Did receipt of seasonal flu vaccine increase the risk of pandemic virus infection?


More videos will be posted during the conference on MicrobeWorld's YouTube Channel

Helen Branswell, Canadian Press, covered this topic in an excellent article yesterday.

La Nina and Influenza Pandemics

A new study published in PNAS by Jeffrey Shaman and Marc Lipsitch finds that the four recent influenza pandemics (1918, 1957, 1968, and 2009) were all preceded by La Niña (colder sea surface) conditions in the Pacific Ocean. The authors suggest that the climate changes can alter migratory bird activity and thus possibly impact their mixing with domestic animals. They therefore hypothesize that La Niña results in a higher likelihood of divergent influenza subtypes coming together with a subsequent higher probability of emergence of novel "pandemic" influenza strains.

In an accompanying BBC story by Richard Black, professor Shaman explains the findings and also cautions that the link should not yet be used to predict pandemics. However, he is hopeful that increased influenza strain surveillance subsequent to recent novel H1N1 and avian H5N1 activity will soon be able to confirm whether their proposed hypothesis is correct.

Reference
Shaman and Lipsitch PNAS 1/17/2012

@eliowa

Contagion - September 9th!!

I know Mike posted about this a month ago, but I saw an ad of the upcoming movie Contagion while watching Cubs/Cards and they've released the opening date. Mark your calendars. If you haven't seen 'Rise of the Planet of the Apes', it's pretty clear that the next "Apes" movie will have a similar global pandemic theme.

Simulating pandemic spread with a phone app?

Source: BBC News

Researchers at the University of Cambridge Computer Laboratory have developed (along with 7 other institutions) the FluPhone app that tracks how people interact and potentially spread influenza or other pathogens.  The app uses Bluetooth technology to anonymously record interactions between volunteers. When cellphones come into close proximity, the interaction is recorded and data is sent to the researchers.

A just-released version of the FluPhone app can transmit fake pathogens to other phones so that the team can randomly "infect" one phone and see how it spreads within the volunteer community. Pretty cool. I wouldn't head to your favorite app store to volunteer just yet, since this study appears confined to the UK and Nokia phones. I actually forgot that Nokia made mobile phones.

Source: BBC News, May 4, 2011

Pandemic Flu: Hit hard, but should we hit early?

Image courtesy of CU Boulder Applied Math
Mathematical Biology Group

When a new pandemic flu strain emerges, as happened in Mexico in 2009, public health interventions such as social distancing are often implemented in the hope of reducing transmission. It is often assumed that the more measures that can be implemented early in the epidemic, the better. However, social distancing policies, while sounding simple, are very costly and typically of finite duration.  It is also unclear, what the policy 'objectives' of the intervention should be. Is the aim to reduce total morbidity/mortality or is it to reduce peak prevalence? How are these aims to be balanced against the societal impact of the interventions? Heady questions indeed.  Fortunately, a new paper in PLoS Computational Biology by Deirdre Hollingsworth and colleagues (including Roy Anderson) poses many of these questions and attempts to explore the intertwined policy objectives of various pandemic flu mitigation strategies.

Using a mathematical model (deterministic SIR model) and assuming a mean infectious period of 2.6 days, an Ro=1.8 and a population size of 58 million (the population of the island of Great Britain), the authors estimated the impact of social distancing interventions on influenza dynamics. They looked at a three possible durations of the intervention: (1) indefinite (2) 12 weeks - the current US policy maximum and (3) until a pandemic vaccine becomes available at 6 months. The also incorporated the use of a limited stockpile of antiviral drugs to limit disease severity and reduce transmission and also looked at the utilization of a partially protective pre-pandemic vaccine during the first 6 months of the pandemic.

What did they find? Well, it is pretty messy, like the truth typically is. One finding that sticks out is that in long-term interventions, there is very little disease incidence before week five, so there is little overall benefit from starting social distancing policies too early. The authors estimate that a few weeks delay in implementing a long-term intervention may result in a higher peak prevalence, but a considerably shorter duration of the epidemic.

What about short-term (12-week) interventions, such as those recommended by the current US pandemic plan? In this scenario, strategies that might contain an epidemic size below a certain level would not be the same ones that could limit peak prevalence. In these scenarios there would be a second peak after the intervention is lifted and they may even result in almost no change in overall epidemic size. For these "short" duration interventions there are no easy answers. For example, if the social distancing intervention is 33% effective in reducing transmission and is started at week 5, it might minimize peak prevalence. However, the same intervention with 22% effectiveness and similar timing would be expected to minimize the epidemic size.

The authors describe and discuss various other scenarios and provide a multitude of estimates for what the effects might be.  However, I think their key contribution is to force us to confront very important policy questions head on.  We need to have discussions about what our policy objectives should be in a pandemic.  Should we aim to limit the total number of cases or should we care about the peak size of the pandemic when our hospital and other public health services are stretched to the limit?  Maybe we should just want the epidemic to end as quickly as possible, so that society can get back to the new normal? We should probably have these discussions before the next pandemic, so we can design the optimal policy to achieve our goal(s). 

Hollingsworth et al. PLoS Computational Biology February 2011

Prior seasonal influenza infections protective against 2009 Pandemic flu (if you're a ferret)

Looking back at the 2009 flu season, I realize how calm it is now compared to then.  I hope it stays that way!  In that pandemic, the attack rate was 50% in young populations compared to perhaps 10% in adults.  Why would this be the case? Serologic analysis showed little cross-reactivity between recent seasonal influenza A(H1N1) viruses and pandemic A(H1N1). The authors of a recent JID paper postulated that the lower attack rate in adults could result from multiple past exposures to viruses with similar B epitopes or since there is conservation of T cell epitopes between pandemic H1N1 and seasonal influenza A, then cellular immunity may also reduce disease severity. There's also the fact that adults responded to a single dose of pandemic H1N1 vaccine, while children did not, suggesting that past exposure to seasonal strains is important.

To examine the role of prior immune reponses in seasonal influenza on exposure to pandemic H1N1, Laurie et al. in the Oct 1 JID, studied the impact of one or two prior infections in a ferret model.  The found that a single prior infection with a seasonal influenza A virus, A/Fukushima/141/2006 (H1N1) or A/Panama/2007/1999 (H3N2), reduced the duration of shedding following challenge with 2009 pandemic H1N1, but not reduce the infection rate nor did it reduce the transmission to other ferrets.

The authors then tested whether two prior infections with seasonal influenza was protective against pandemic H1N1.  They determined that infection with seasonal A(H1N1) followed by A(H3N2) reduced the infection rate along with the amount and duration of shedding in ferrets challenged with pandemic A(H1N1). Interestingly, no virus was transmitted to other ferrets, nor did the exposed naïve ferrets experience seroconversion to pandemic flu.

Good news, if you're a ferret.

Laurie KL, et al JID, October 1, 2010.

Let the “false pandemic” debate begin!

Last Spring, we had quite a few posts about whether the emergence of H1N1 should be termed a pandemic. Turn back the clock, ‘cause it looks like we’re going to have that debate all over again. What self-respecting pandemic virus kills fewer people than seasonal influenza?

Read it for yourself, but the Council of Europe just passed a resolution calling for an investigation into the role of big pharma in the WHO decision to declare a pandemic. An emergency debate is scheduled for later this month…..pass the popcorn, this should be interesting.

Chart of the day

Today's New York Times has an interesting graphic of deaths due to influenza and pneumonia during the pandemic of 1957-58. CDC is using this to encourage vaccination against H1N1 in the event that a similar subsequent spring peak is seen.

New Year's Resolutions, Procrastination and Public Health

I suspect we've all made resolutions at some point, but studies show most of us fail to accomplish our goals. I mean, is Lindsay Lohan really going to stick to this? I give her until St. Patrick's Day, but I digress.

In a recent article, The Economist suggests that a major reason for our failure to accomplish our goals is that we have a tendency to procrastinate; no surprise there. We tend to put off unpleasant or costly things into the future. That would be OK if we would stick to a single delay, but it turns out that we are time-inconsistent or “present-biased” and will always put off tough or costly things to the next day. Tomorrow really is always a day away. They reference a paper by O’Donoghue and Rabin.

I suspect this tendency is at the heart of the public health problems we have in the US. When you build a road you have immediate gratification, but the gratification of a well-funded state health department is uncertain and certainly in the future. Perhaps a better example is one I suspect many of us in infection control will soon face: should we push our administration to restock our N95 mask cache that we used to meet the OSHA/CDC/IOM requirement to care for suspected H1N1 cases? Avian flu is still out there and is just as likely to become a pandemic as it was last year.

This issue really concerns me. Even in this mild pandemic, we all saw how quickly the supply chains dried up for critical supplies. However, I suspect that hospital administrators will assume that the next pandemic will be this mild or forget the supply chain difficulties we had. Even more of a concern for me is procrastination. Will they assume that they can delay purchasing N95s for a cache because we just had a pandemic so the next one won't happen soon? They can "wait 'til next year" just like our favorite Cubs fan. The problem is that next year they will wait until next year.

Fortunately, the Economist and authors Duflo, Kremer and Robinson offer a potential solution using an example of why so few African farmers use fertilizer and how this can be improved. The quick answer is that the tendency to procrastinate can be overcome by small upfront time-limited subsidies. This small investment ends up being far less costly than doing nothing or offering a larger subsidy later in the year. What this suggests is that public officials should offer a grant to hospitals who invest in their pandemic cache (mask, antivirals etc) in the next year, but remove the subsidy quickly. This could overcome the inertia to do nothing because of pandemic fatigue or procrastination. Of course, how can we overcome our public officials' tendency to procrastinate? They do have bridges to fix. Thoughts?

I got nothin'

I'm too busy doing H1N1 response (it is the new Ebola!). Our community epidemic is picking up speed, so we are setting records in our Emergency Department, where 15% of the visits are now for influenza-like illness. Pages, e-mails, and drop-ins are eating up almost every spare minute for our infection prevention staff. Is [fill in the blank] an aerosol generating procedure? Why don't you have filters on the ventilator exhaust? Why won't you give the injectable H1N1 vaccine to [fill in with any person not on our current list of approved recipients]? I heard they had vaccine in [random location], why don't we have it available here? [Hospital X] is not allowing anyone under 18 to visit, why haven't we made that our policy? How come we aren't using N95s for all patient care, don't you know the CDC recommends it?

If I had time, I'd put a link here to the sound of a primal scream.

Stupid

To quote David St. Hubbins, "it's such a fine line between stupid, and clever." I'm listening right now to the CDC conference call on their new infection control guidance, and I reluctantly conclude that they've crossed that fine line. This is stupid.

How much actual, front-line, hospital-based infection control experience do these CDC, OSHA and NIOSH experts have? And to paraphrase an e-mail I recently received from a colleague: "when did influenza become Ebola?"


Addendum: See below for excerpts from SHEA's response, with which I agree:

Scientific Community Urges Thoughtful Application of New CDC Guidelines Regarding H1N1 Prevention and Protection Procedures

Infectious Disease Experts Express Concern over N95 Recommendations; Support CDC’s Call for Multipronged Approach

Today’s announcement by the Centers for Disease Control and Prevention (CDC) that it is modifying its guidance regarding measures that should be taken by healthcare workers who are in contact with either confirmed or suspected cases of H1N1 was met with concern by the scientific community that had submitted its recommendations to CDC.

CDC emphasizes a multipronged approach to protecting healthcare workers from H1N1, including priority use of N95 fit-tested respirators. The Society for Healthcare Epidemiology of America (SHEA) had urged CDC, based on clinical experience and scientific evidence, to remove the use of N95 respirators from its recommendations for routine care in favor of the first-line use of surgical masks, as one component of a cadre of prevention measures. Instead, N95 respirators should be reserved for procedures associated with a higher risk of aerosolization of the virus.

“Our position was and continues to be that N95s are neither necessary nor practical in protecting healthcare workers and patients against H1N1,” said Mark Rupp, MD of the University of Nebraska Medical Center and President of SHEA. “The best science available leaves no doubt that the best way to protect people is by vaccinating them.”

The scientific community acknowledged that the CDC came under intense pressure from labor unions to recommend the use of N95 fit-tested respirators despite the fact that respirators do not provide any added protection in clinical situations against droplet transmissible diseases such as H1N1. SHEA, whose membership is comprised of doctors and nurses on the front lines caring for patients with the flu, emphasizes the concern that continuing to recommend that respirators be used in routine care has major implications for both patient care and healthcare worker safety. “We could actually put healthcare workers at greater risk by further reducing an already short supply of a device that is needed for high-risk procedures such as bronchoscopy by using it for routine care,” said Rupp.

.....“unfortunately this debate on respirators versus masks has distracted hospitals and clinics from investing in efforts that we know will pay off such as rigorous and consistent application of basic infection control and personal hygiene practices including adherence to cough etiquette and hand hygiene, rapid identification and separation of patients with the virus, and excluding sick workers and visitors from the hospital.”

State versus Feds

One thing I’ve been pleasantly surprised by during this H1N1 season is the willingness of some state departments of public health to issue guidance that differs from that of the CDC. I’m a little surprised that the media hasn’t paid more attention to this.

CDC says all health care workers with ILI should stay home for 7 days? Iowa says nah, come back if you’ve been afebrile for 24 hours and your cough has improved.

CDC says wear an N95 mask for all direct contact with patients with suspected H1N1? Iowa says no, surgical masks are fine except for aerosol-generating procedures.

On the one hand, this makes it easier for hospitals like ours to establish sensible, and feasible, policies during the long H1N1 season….on the other hand, neither the state public health department nor the CDC is going to come in to your hospital and slap you with a big fine. OSHA might….and they will require you to follow CDC guidance.

So maybe, one day, CDC and OSHA will get their collective “stuff” together and issue guidance that actually makes sense for busy, understaffed hospitals, and that can be sustained through future influenza seasons (since H1N1 is, after all…..an INFLUENZA virus).

Infection prevention: The media backlash!

A couple news articles today are designed to generate annoying e-mails to tired infection preventionists….

The first story, from CNN, is really a non-story that takes the fact that influenza is a respiratory virus (that spreads, you know, from respiratory droplets) to insinuate that hand hygiene is not an effective flu prevention measure. Numerous experts are cited, not all of them say the same thing.

The second is a bigger deal, because it appears to already be affecting vaccine policy in at least one Canadian province. Apparently some Canadian studies have linked prior receipt of seasonal flu vaccine to an increased risk for H1N1 infection. The news account is here and I wish I could link to the study data—but it isn’t published and won’t be released by the investigators until it is peer-reviewed (then why leak it to the media, is my question…..). Tom Frieden had little to say about this issue at the CDC press conference, except that data from the U.S. and Australia have not shown such an association.

Light posting this week....

Sorry about the infrequent updates this week. As many of you are no doubt doing, I’m still spending a lot of time dealing with H1N1-related issues. We already have a shortage of N95 masks, so have been working with units to educate them about re-use. H1N1 vaccine may be arriving sometime in early October, in limited quantities, so we are busy prioritizing risk groups for vaccination. We are also starting to see symptomatic healthcare workers in our employee health clinic for testing (we are testing those who meet “influenza-like illness” criteria in an effort to get those who test negative for H1N1 back to work sooner than the current CDC recommendation of 7 days). Meanwhile, our state department of public health is preparing to recommend that healthcare workers can return to work after 24 hours afebrile with improvement in other symptoms. We’ll soon be in a situation where our state department of health has substantially different recommendations than CDC for both isolation precautions (surgical vs. N95 masks) and healthcare worker sick leave. Unless the CDC issues updated guidance soon…..

Time for another reality check—pneumonia and influenza mortality remains below the epidemic threshold:

Sufficiently bored now? Then read more about MRSA everywhere, this time in our favorite animals….

Drowning in swine flu garbage (literally)

Remember when Egyptian authorities, spurred on by pandemic hysteria, made the misguided decision to kill all that nation’s pigs? Turns out those pigs processed (i.e. ate) most of Cairo’s organic waste! Without the pigs to eat it, that waste is now piling up in rotting, stinking heaps.

Balancing patient safety with patient safety

Mike has already pointed out the degree of uncertainty surrounding how to prepare for (and respond to) the spread of novel H1N1. One of the challenges is maintaining a focus on overall patient safety and the potential unintended consequences of our H1N1 response.

One example that comes to mind is the question of how long to keep ill health care workers (HCWs) at home after their symptoms improve. The current CDC guidance suggests HCWs stay at home for at least 7 days after onset of “febrile respiratory illness” (temp greater than 37.8 C and cough or sore throat).

This may not be a problem now, but soon there will be a multitude of circulating respiratory viruses (see here for a partial list). If it is a bad “respiratory virus season”, even if H1N1 represents a minority of the circulating viruses, then a very large number of HCWs will be staying home from work for at least a week. And we know that understaffing is a problem for patient safety.

What are the alternatives? Three that come immediately to mind include: (1) sending HCWs back to work once they are afebrile for 24 hours, as the CDC is now recommending for schools and other workplaces, (2) sending HCWs back to work once afebrile, but making them wear a mask until the 7 day point is reached , or (3) screening all sick HCWs with a test that has a rapid turnaround time and high negative predictive value, and sending those that are negative for influenza A back to work once symptom-free and afebrile. Investigators from Beth Israel-Deaconess in Boston recently reported a negative predictive value of 96% for the rapid DFA test.

As Mike alludes to in his post, the most important thing is to remain flexible, and nimble, realizing that the response to novel H1N1 will evolve with the pandemic. Many hospitals will try initially to adhere to CDC guidance, but must be willing to modify their approach if they begin to experience staffing shortages that threaten patient care.

Institute of Medicine to weigh in on PPE for influenza

We’ve blogged extensively about the discordance between CDC and WHO guidance on the use of personal protective equipment (PPE) while caring for H1N1 patients in healthcare settings. You can read our posts on this here, here, here and here.

Looks like IOM is now going to weigh in. You can find their project scope (or “charge”) here, along with links to the committee membership. The project specifies “novel H1N1”, but that seems very silly to me. No robust data exist to suggest that transmission of the novel H1N1 differs in any substantive way from that of seasonal influenza. So any conclusions or recommendations that come from this committee should be applicable to all influenza viruses, not just the “novel H1N1”.

The ad hoc committee has to report its findings to CDC by September 1st. So what do you think the likelihood is that we’ll be using N95s for care of all patients with seasonal influenza, every year?

Postcard from Latin America #5

Dr. Richard Wenzel writes from Argentina:

Schools are closed, and will be for 4 weeks, and all high risk, young adults (e.g., pregnant women) are not allowed to work. Only young adults screened at hospitals can get oseltamivir. Met with the Minister of Health of Buenos Aires, and he told me yesterday that of 85 deaths in the region - half of the total deaths in Argentina- one fourth were in pregnant women. In Sao Paulo, Sergio Wey told me that there pregnancy was the leading risk factor for severity. In Argentina obesity is a close second risk factor for dying with H1N1. Also in Argentina I was told that diarrhea occurred in 10-20 percent, in the 12 percent range I heard about in Mexico. So far no one has tested stool for virus. I also heard about severe cases in Chile and Argentina in solid organ and bone marrow transplant patients. Not sure how many were nosocomial.

Postcard from Latin America #4

Dr. Richard Wenzel writes from Chile:

Made rounds in the adult and peds ICU of one of the university hospitals- hospital clinico UC. They nodded concurrence that about one-third of non-icu admissions have no fever. More interesting they volunteered that half of the outpatients with H1N1 confirmed had no fever. Each had anecdotes that they have screened patients with rhinorrhea only and confirmed H1N1. The point is that the clinical expression of H1N1 is extremely broad. Obviously screening patients with fever will miss many. Lastly, for counting patients, if fever is part of the case definition, the denominator will be greatly underestimated.

The adult in the ICU was an obese 34 year old man whose weight was 150 Kg and BMI was 40. Obesity was recognized informally in Mexico City when I was there earlier. The recent MMWR notes obesity as well. Obviously the question is whether the weight per se is an issue, and maybe these patients have no reserve when they get viral pneumonia. However, I suspect that insulin resistance is a factor: many have underlying hypertension and diabetes (i.e., metabolic syndrome).

Of interest is how H1N1 is managed in Chile vs Brazil. Here clinicians make a clinical diagnosis- confirmation is not essential - and order oseltamivir. The drug is given to patients free of charge.