Operational Biosurveillance

The Use of Forecasting to Rapidly Identify Non-Routine Infectious Disease Signatures: Part 2

Our team has been doing a full review of outpatient / inpatient / transfer stats from our department's perspective for Jan-Mar 2012, which was a time period where we saw an epidemic of human metapneumovirus (hMPV) that overlapped an unusually severe season of RSV. We have issued several reports of our experience here in this blog.  In Part 2, we explore further the "so what" of operational infectious disease forecasting coupled to early warning. 

On the 25th of every month the Ascel Bio Black Canyon Infectious Disease Forecasting Station released forecasts for infectious disease activity specific to our county.  RSV and other respiratory pathogens were therefore expected to appear and cause a given level of strain to our medical infrastructure. 

From Jan 4th to Feb 10th, we admitted a low number of patients exhibiting typical RSV infection, where we followed American Academy of Pediatrics (AAP) guidelines for the management of RSV: no antibiotics, steriods, with the rare use of inhalers.  In the midst of these admissions, the Station issued an advisory for unusual human metapneumovirus activity which at the time was primarily disruptive to the outpatient component of our medical infrastructure.

Then, from Feb 12-16th, multiple back to back admissions presented as typical RSV infections but abruptly decompensated on the floor, precipitating transfers for all of them to the Front Range by fixed wing aircraft.  In the midst of this, we were told the Front Range's PICU grid capacity was close to diversion status.  It was during this time we had report from the PICU that received our patients they were coinfected with Haemophilus influenzae.  One of these patients would later be triply infected with Streptococcus pneumoniae while intubated.

On Feb 18th, a warning was issued by the Station, indicating an unusual epidemiological situation now existed for epidemic RSV of high clinical severity.  Our department issued guidance to abandon standard AAP protocol for the treatment of RSV and consider the use of antibiotics prophylactically given the apparent high coinfection rate being seen.

Results:

Before the warning was issued to all providers with pediatric admitting privledges, our hospital exhibited a 33% transfer rate, all of whom were over the course of four days.  Of those transferred, none of the patients were given antibiotics prophylactically upon admission.  Forty-six percent of all admissions pre-warning were provided antibiotics for comorbid conditions such as otitis media.

After the warning was issued, the transfer rate dropped to 8%, as now 88% of RSV admissions were provided antibiotics prophylactically.  Of total admissions to the hospital during the entire epidemic of RSV, 71% of the admissions were seen during the post-warning period.  The 8% who were transferred were placed on antibiotics prophylatically, however it is not clear they were truly infected with RSV.

Adherence to the Station's warning heeded at least a 76% reduction in transfer rates due to RSV during the epidemic. 

This is one of the rare examples of operational validity and proof of performance using near real time surveillance coupled to operational forecasting that altered the outcome of an epidemic.

 

 

 

 

 

 

 

Successful Operational Forecast: Influenza Vaccine Drift

Approximately one year ago, our team produced a series of forecasts for influenza vaccine drift anticipated to occur in the 2011-2012 northern hemisphere influenza season.  Today's ProMED post by the influenza group at the British Columbia CDC has provided affirmation of these forecasts, which were available to us months prior to the appearance of influenza in our patient catchment area. As noted here, we have been tracking clinical reports of patients infected with influenza who were previously vaccinated, some of whom died.

This again highlights the value of forecasting and early warning that has been reduced to practice in the clinical setting to rapidly recognize non-routine infectious disease signatures.

ADVISORY (Updated): Influenza in Previously Vaccinated Patients (Pacific NW and Colorado, USA)

Per our prior Advisory, we have report of another metropolitan hospital in the Pacific NW seeing influenza in previously vaccinated children. 

Here in western Colorado, we saw the death of an elderly woman who had a prior medical history of chronic pulmonary disease.  Both she and her husband were vaccinated for influenza, but the husband was the first to be infected, then the wife who later succumbed.

A notable phenomenon given we forecasted this outcome months ago for our hospital, prior to the advent of influenza season.

Several comments from readers indicate a healthy debate related to a chicken-egg problem: is what we are seeing true vaccine drift or simply a poor vaccine match in the first place?  A tricky question to answer...

ADVISORY: Influenza in Previously Vaccinated Children (Pacific NW, USA)

We have report of a significant bump in influenza-positive pediatric patients presenting to a major metropolitan hospital in the Pacific NW, USA over the last 2-3 weeks.  Of note, many of these patients were previously vaccinated for influenza at the start of the school year (~September). 

 

Differential diagnosis (in order of probability):

1. Waning immunity as the predominant type A influenza circulating is H3N2 in the Pacific NW.  Waning immunity over the course of a routine influenza season is an expected phenomenon.  Our team forecasted a moderate vaccine drift probability for A/H3N2 this season several months ago.

2.  Waning immunity as there are still significant levels of circulating A/H1N1 (2009) in the Pacific NW.  We believe this is highly unlikely and forecasted very low probabilities of vaccine drift for A/H1N1.

3.  Possible emergence of other type A influenza viruses such as A/H3N2-variant.  While we believe this is unlikely, we cannot exclude it.  One of the key indicators we have been monitoring is the appearance of influenza in patients who were previously vaccinated.

The Use of Forecasting to Rapidly Identify Non-Routine Infectious Disease Signatures: Part 1

Our team has been doing a full review of outpatient / inpatient / transfer stats from our department's perspective for Jan-Mar 2012, which was a time period where we saw an epidemic of human metapneumovirus (hMPV) that overlapped an unusually severe season of RSV.  We have issued several reports of our experience here in this blog.

The forecast, initially released by the Ascel Bio Black Canyon Infectious Disease Forecasting Station in Nov (i.e. 60 days before the onset of RSV and non-RSV activity), indicated we would see RSV activity precede non-RSV (i.e. human metapneumovirus, hMPV).  We should have expected higher RSV activity than MPV in Jan. 

What actually happened:

More MPV activity in Jan than RSV, with RSV exhibiting nearly zero activity (grossly unusual based on prior baselines, as indicated by the forecast).  This tipped us off immediately we were seeing something not observed at least in the last 5 years.  We were the first in the nation to publicly declare the possibility of a "bad" / unusual season of RSV/MPV; this was confirmed by multiple pediatric intensive care units in many other states.

Our department saw +180%, +213%, and +180% hospital admissions for the months of Jan, Feb, and Mar 2012, respectively, based on prior baselines.  From the perspective of total pediatric admissions for Jan-Mar inclusive, we saw a difference of +238%.

From the perspective of transfers from inpatient care to an outside facility (i.e. due to level of acuity), we transferred +100%, +746%, and +150% for the months of Jan, Feb, and Mar 2012, respectively, based on prior baselines.  The expected average transfer rate for Jan-Mar, inclusive, was 7%.  What we saw in Jan-Mar 2012 was 13% (an increase in clinical acuity of 186%). 

The unusually high clinical acuity triggered a change in clinical protocol based on report of bacterial coinfection (e.g. Haemophilus influenzae, among other)- we are still analyzing the data to see if there is an inference of transfer avoidance after implementing this protocol.  It is notable that the number of transfers for Jan-Mar 2012 was +160% over the combined transfers for Jan-Mar 2009, 2010, and 2011, and +480% over the expected average annual Jan-Mar period.

Conclusions:

1.  The 2012 RSV / MPV season broke all available hospital records in terms of admission volume and clinical severity. 

2.  The forecast was accurate, and highlighted a subtle difference in the 2012 disease activity signature that empowered us to rapidly recognize unusual disease activity early in the season involving RSV and MPV.  This then empowered us to alert colleagues nationwide about a change in RSV/MPV activity.

Round 2: The Black Canyon Forecasting Station Versus Google's FluTrends, ProMED, And SickWeather Combined

Round 2. 

The first such comparison generated quite a bit of Internet traffic.  Record-breaking for this blog, in fact, from multiple countries around the world.

Here again we perform a simple comparison between information produced and made available to the public by the Black Canyon Infectious Disease Forecasting Station (#1) and the combined output of Google's Flu Trends, ProMED, and SickWeather.  Screenshots from these websites were taken at approximately 2130 on 19 Feb 2012.

 

Black Canyon Infectious Disease Forecasting Station.

As previously noted, we forecasted in December a surge in patient volume and clinical severity due to a variety of viral respiratory pathogens, notably RSV, for our specific location in the US: Delta County, Colorado, which is near Grand Junction (geographic coordinate Lat/Long: 38° 44' 43.4394", -108° 2' 49.1994").

We indeed did see this, along with the forecast-facilitated detection of unusually severe, high volume RSV disease related to coinfection with other pathogens.  Here in Colorado, this has produce pediatric infrastructure strain at a grid level, meaning near-diversion status for several PICUs along the Front Range (our referral loci).  We were warned that beds may not be available the next time we needed to execute a transfer...

The entire staff complement of our office was infected, yet again, but no one took time off.  Much misery among staff working very long hours, with physicians pulling 48 hr call that afforded little sleep.

 

Google Flu Trends.

Again tells us we are at "moderate" levels of influenza. 

We have not documented a single positive specimen to-date in our clinic.  We are aware of a clinic 20 miles east of us that documented two positive cases in their kids about ten days ago- no activity since.

 

ProMED. 

Absolutely nothing on Colorado.

 

SickWeather.

Thirteen (13) different symptoms selected, as shown below.  One single report of "pneumonia" submitted.  Nothing else.  We were unable to obtain evidence of true pre-event operational forecasting in the SickWeather website.

Summary.

Again, the limitations of using open source information and social media is revealed.  We just experienced an unusual, non-routine infectious disease signature pattern in our county that resulted in significant medical infrastructure strain and near-diversion status at the grid level for the pediatric critical care infrastructure in our state.  There is no indication of this significant level of infectious disease activity in Google's Flu Trends, ProMED, and SickWeather combined.

The Black Canyon Forecasting Station in "War Time Operations"

This is a local healthcare community WARNING posted today by the Black Canyon Infectious Disease Forecasting Station.  Of note, this is a warning related to mostly non-notifiable infectious disease- thus reflective of the socialization process of routine infectious disease forecasting analogous to meteorological forecasting as a vital component to community health.  Public health is certainly a partner and involved, but until a notifiable disease is involved, they do not engage.  Meanwhile, we are dealing with near-maximum patient volumes, clinical severity, and awareness of an entire medical grid strained (which effects our decisions to transport to critical care facilities).

 

A new epidemiological situation in Delta County has been detected by the Black Canyon Infectious Disease Forecasting Station over the course of the last week.

The forecast for February (first issued in December) called for heightened activity levels of multiple pathogens, including RSV, human metapneumovirus, adenoviruses, coronaviruses, influenza A and B, and Moraxella catarrhalis, among other pathogens.  The forecast also indicated we would reach maximum medical infrastructure strain this month, and indeed we and the entire state have been experiencing this- multiple PICUs on the front range are at near-diversion status.  What is remarkable is this is NOT due to influenza virus, as we have had a remarkably mild season (again, as forecasted). 

The current situation represents expected high RSV transmission in the community.  What is not expected is the older age of children involved and the clinical severity- we are seeing an abrupt and unusually high volume of admissions, clinical severity, and age of our patients (2 to 2.5 year olds).  Of significant concern is the atypical pattern of these patients exhibiting apparent clinical recovery, then abruptly decompensating and requiring intubation and transport to facilities with more appropriate critical care facilities.  We have discovered there is an (apparent) high and unusual rate of RSV coinfection with other pathogens such as human metapneumovirus, adenovirus, Moraxella, and notably for Delta County, Haemophilus influenzae.  PICUs in our transport referral area are indicating a rare rate of coinfection with influenza A.  RSV coinfection, in general, is often associated with more severe and life-threatening complications.  Consultation with pediatric emergency departments and PICUs nationwide resulted in reports from several areas of the country indicating similar patterns.  We continue to receive updates...

When influenza is exhibiting its typical level of activity, transmission activity produced by these other pathogens are thought to be suppressed in the community by mechanisms still as-yet unclear.  While the forecast of a mild influenza season initially appeared to be "good news", in this case it revealed a disruptive phenomenon involving multiple pathogens (with RSV leading the way).

James M. Wilson V, M.D.
Chief of Station
Black Canyon Infectious Disease Forecasting Station
-and-
Department of Pediatrics
Delta County Memorial Hospital
Delta, Colorado

 

The other important phenomenon is the social network that has evolved around operational forecasting.  Physicians simply come forward quicker with information vital to confirm signals that would otherwise be missed.  This, of course, is a crucial sociological process when contemplating rapid recognition of non-routine or unusual infectious disease activity signatures.

 

 

Peaking Activity of hMPV Confirmed in Multiple US Cities

Cross-checking with other pediatric colleagues nationwide has revealed that yes indeed, from Rhode Island to Chicago to Dallas pediatricians are noting a substantial level of hMPV activity.  Technology is surely a factor here, where we are actually able to 'see' this pathogen via molecular diagnostics. 

Let it be said, we are seeing a sociological shift in our medical colleagues in even discussing this pathogen in the first place, which has largely been ignored because such recognition did not change clinical management.  Important because of a social shift in understanding our country's baselines of biological activity.  Such finer understanding and discourse about this pathogen feeds into the process of developing our core of "astute clinicians" so important to rapidly recognizing unusual biological activity signatures in our country.

 

 

Pediatricians Testing All Admits For Human Metapneumovirus (hMPV)

We have become aware of word that some local pediatricians are testing all admits in Indiana for human metapneumovirus (hMPV).  In Colorado, an increase in activity has been observed, activity that was forecasted by the Black Canyon Station weeks ago, as previously posted. 

What is crucial for anyone in government observing this phenomenon is the first operational demonstration in the US of a National Weather Service-inspired infectious disease forecasting process that

1. presented a pre-event probablistic-based forecast that was deliberately used by clinicians to
2. ask important questions in the context of a subsequently detected emergent infectious disease phenomenon;
3. rapidly recognize the etiology of the phenomenon; and
4. report it out to others for net-centric awareness
5. at a sub- official public health notification threshold
   

Of course, this was routine procedure in the first 150 days post-quake in Haiti.  Operational infectious disease forecasting is a critical social primer to tighten the delta between anticipation-detection-recognition-warning-response. 

Note this process has further facilitated the 'digestion' and habituation of healthcare providers to ask specific questions about a virus that was previously unknown but endemic and routine.  Indeed most physicians have only care about the question "bacterial versus viral", ignoring the important microbiology behind the question that determines treatment and prognosis.  While knowing what the virus is does not change clinical management at this point in time, it does provide an important risk communication tool for our patients and their families: resolution of uncertainty.  This is such an important part of the physician-patient communication.

The key question to ask now is whether genomic sequences should be obtained, and an epidemiological workup should be entertained.  hMPV does exhibit genomic variability similar to RSV- therefore, we may be seeing a "bad" year of hMPV versus unmasking of activity due to low influenza and RSV activity. 

Either way, the question should be asked if pediatricians are now testing all admissions for hMPV...

 

The Black Canyon Forecast Station Versus Google's Flu Trends, HealthMap, and SickWeather

Here we conduct a simple comparison between the output of the Ascel Bio Black Canyon Infectious Disease Forecasting Station, Google's Flu Trends, HealthMap, and SickWeather.  We are going to compare the output of the enhanced forecast provided by the Black Canyon Station that includes integrated national and local health intelligence data. 

 

Black Canyon Infectious Disease Forecasting Station

Currently, we are dealing with a probable large-scale seasonal outbreak of human metapneumovirus (hMPV) here in Delta County, Colorado.  Large enough we saw two more families affected with several more RSV- and influenza-negative cases of pneumonia.  Disruptive enough to keep a large portion of our patients out of school for days as well as moms and dads.  Disruptive enough to infect 2/4 of our clinical staff, prompting time off to recuperate and infect a third who worked through her illness. 

This event represents a validated forecast specific for both the clinical syndrome and pathogen issued 30 days ago for the geographic coordinate Lat/Long: 38° 44' 43.4394", -108° 2' 49.1994" (Delta County, Colorado).

Pneumonia, as forecasted, has reached a peaking score on the Infectious Disease Medical Impact Scale (IDMIS), which indicates we are reaching an expected level of strain in terms of incidence and clinical severity. 

RSV bronchiolitis is creeping upward as well, in keeping with forecasted expectations.  Influenza activity has been zero in our pediatric population, meaning to-date we have not had a single positive test for influenza.  Acute URI, otitis media, and bronchitis have all been observed, consistent with our forecasts.  We are aware that Group A Streptococcus, rhinovirus, hMPV, adenovirus, and coronavirus are circulating at heightened levels as well- all of which were also forecasted.  ... And this is but a snapshot of the nearly 100 diseases the station is currently forecasting and tracking live.

All disease activity considered, we are approaching our peak clinical load in terms of combined disease incidence and clinical severity, with evidence of mild infrastructure strain due to healthcare worker illness and absenteeism.

 

Flu Trends

This is the most current Flu Trends view of the state of Colorado regarding influenza:

The team at Google provided the following statement to the journal Nature:

Because the relative frequency of certain queries is highly correlated with the percentage of physician visits in which a patient presents with influenza-like symptoms, we can accurately estimate the current level of weekly influenza activity in each region of the United States, with a reporting lag of about one day.

According to Google, we are now at moderate levels of influenza for the state of Colorado.  This is grossly incorrect.  We have not seen a single positive influenza sample in any of our patients in our county, which is located west of the Front Range.  To quote the latest influenza surveillance report from the State Department of Health, which utilized data up to Jan 28th, which is 5 days before the Flu Trends graph:

For the week ending January 28th, influenza activity remained low but increased somewhat based on sentinel hospital lab data and influenza-like illness (ILI) data. Influenza activity remained along the Front Range, as well as the northeast and southwest parts of the state.

According to the above Flu Trends graph for the state of Colorado, we were moving away from low levels of influenza activity in mid September. 

Had we used Flu Trends, we would have been told there was moderate activity when activity was clinically non-existent.  Further, there is no indication of whether influenza was at worse levels than prior years.  In essence, a useless source of information for the purposes of operational biosurveillance or clinical medicine. 

 

HealthMap

Below is a screenshot, taken on Friday, Feb 3, 2012 at 2000.

What is remarkable is the appearance of minimal infectious disease activity, not only for Delta County (which is located southeast of Grand Junction), but for the entire state of Colorado.  This is most certainly not the case. 

Clicking the only two pins shown for the state of Colorado reveals the following:

This is the limitation of solely relying on media reports and other internet-based reporting of infectious disease events.

 

SickWeather

SickWeather recently tweeted:

"#doctors #nurses be prepared for #patients - see what's going around this #cold & #flu season using http://t.co/9z59kOFA"

Had we been using SickWeather's map for our clinic, it too would have failed us.  Below are screenshots of all of the symptoms we are seeing.  There is no indication, based on the SickWeather mapping of the Western Slope, of the volume and clinical severity of the illnesses we are now seeing as physicians.

[The above figures were updated per SickWeather's comment- to be fair to them!]  The only symptom displayed by SickWeather is pneumonia, with no indication of the true pervasiveness and severity in our kids that we are seeing.  What would be interesting is to see how long that signal had been there and how closely it matched our clinical records.  Either way, we have been issuing pre-event forecasts for pneumonia in our area for weeks prior to its appearance.

SickWeather claims to forecast infectious disease activity,

however this is incorrect and misleading.  There is no pre-event (meaning an expression of what will happen before the event has actually occurred).  It is highly doubtful that a patient would tweet a symptom before our knowledge of what was already happening in our community.  Particularly regarding events of significance such as the outbreak of viral pneumonia we are seeing and associated medical infrastructure strain at the outpatient level.

 

Summary

The combined consideration of situational awareness provided by Flu Trends, HealthMap, and SickWeather failed to provide an accurate picture of current infectious disease activity in Delta County, or even the state of Colorado.  None of these capabilities provided true forecasting of infectious disease activity.

While flashy, web-based technologies capture the attention and fancy of the media, academic journals, TED talks, blogs, and the like, there remains the practical reality of the need for experienced professionals to choose the appropriate data, assess the significance of the information, and practically answer the "so what" question.  The current operational state of the art actually does not predominantly use the data provided by technologies such as Flu Trends, HealthMap, or SickWeather. 

To place the world of operational biosurveillance in context, we often use the Microscope Analogy:

We consider open source / web-based event or horizon scanning, as offered by Flu Trends, HealthMap, or SickWeather, to be analogous to the low power lens of the microscope.  The low power lens helps one become oriented to a specimen slide (i.e. a given location in the world), especially if one has not seen that slide before.  Syndromic surveillance data represents a medium power lens.  Clicking further as one zooms in for more comprehensive detail, one is using clinical laboratory diagnostic data. 

This is precisely how the Haiti Epidemic Advisory System functioned.  Initially open source information was used for orientation prior to deliberate social network engineering.  Eventually, open source information was discarded in favor of direct ground observations and clinical data.  One could not execute emergency medical response that included helo drops based solely on open source data.

It is important to view the media hype and the marketing around these technologies with a skeptical eye... because operational reality is quite a bit different: better accuracy, far faster, more complex, operates in the pre-event domain, and has been used clinically on a daily basis.