Foodborne, Waterborne and Zoonotic Infections Division

Foodborne, Waterborne and Zoonotic Infections Division


Syndromic Surveillance Using OTC Medication Sales…How Useful Is

It?

Victoria L. EdgeFoodborne, Waterborne and Zoonotic Infections Division

Infectious Disease and Emergency Preparedness

COMOH/APHEO Education Session for Syndromic Surveillance

1st February 2007


Objectives

C. Understand the role of, and interactions between, public health representatives at different gov’t levels and pharmacists

A. Understand how OTC data are collected and categorised – the importance of researching historical data.

B. Understand the difference between using spatio-temporal patterns of OTC sales as an early warning system and for routine surveillance.


On the Agenda…

• OTC data surveillance

• Public Health Agency of Canada’s (PHAC) use of OTC data

• Features & Utility

• Challenges

• Advantages


OTC Data Surveillance


A. S. A .P.

Alternative Surveillance Alert Project

https://www.cnphi-rcrsp.ca/cnph


Early warning of community outbreaks.

Investigate significant historical Canadian outbreaks.Waterborne :

• Walkerton, Ontario E.coli O157 and Campylobacter

• Battlefords, Saskatchewan Cryptosporidium


Walkerton, Ontario

Spring 2000

Waterborne outbreak: E.coli O157 and Campylobacter


A. S. A .P.


• Meeting with area pharmacists and PHU representatives

• Collection of data – only one pharmacy able to provide electronic data (in weekly format)

• Compared with confirmed (lab) cases from outbreak investigation and also with IGI–related ER visits data


Culture confirmed cases (onset+4days) and Weekly Totals of OTC Culture Confirmed Cases by Onset + 4days and Weekly Totals of

Over-the-Counter Medications Walkerton (March-June2000)

0

10

20

30

40

50

60

70

80

Date

Un

its S

old

0

5

10

15

20

25

30

35

40

45

50

Nu

mb

er

of

Cases R

ep

ort

ed

OTC sales

Cases reported to Health Unit(onset+time lag of 4days)

Heavy rainfall.

(8-12th May)

Start of outbreak

period. (13th May)

Boil water advisory. (21st May)

Start of outbreak

period 13th May

Ref: Edge et al., 2004. Can J Pub Health 95(6):446-450

Walkerton, March-June 2000


Battlefords, Saskatchewan

Spring 2001

Waterborne outbreak: Cryptosporidium


OTC medications related to IGI epidemic curve realized in a retrospective investigation of a waterborne outbreak of

Cryptosporidium.

North Battleford, Saskatchewan Spring 2001

0

5

10

15

20

25

30

35

40

45

50

55

60

01-Mar 10-Mar 17-Mar 24-Mar 31-Mar 07-Apr 14-Apr 21-Apr 28-Apr 05-May 12-May 19-May

Date

#C

ases

epi-linked, unconfirmed (n=929)

confirmed +7day lag

MAR 21

Water system compromised

APR 25

Boil Water Advisory

(Ref: Stirling R, et al. 2001. ) http://www.health.gov.sk.ca/info_center_pub_health_can_epi_report_

NB.pdf

0

5

10

15

20

25

30

35

40

45

50

55

60

01-Mar 10-Mar 17-Mar 24-Mar 31-Mar 07-Apr 14-Apr 21-Apr 28-Apr 05-May 12-May 19-May

Date

#C

ases

0

20

40

60

80

100

120

140

#U

nit

Sale

s

confirmed +7day lag

epi-linked, unconfirmed (n=929)

2001 Sales

MAR 21

Water system compromised

APR 25

Boil Water Advisory

(n=110)


A. S. A .P.


How PHAC uses OTC data


A. S. A .P.


Key Observations from Initial Research:• Keep ‘human involvement’ to a minimum

• Keep it simple : for public health officials

for retailers and pharmacists

• Define benefit: for public health

for retailers and pharmacists


A. S. A .P.


PHAC’s Objectives:• Create and test a system of OTC-sales based surveillance operating at the national level

• Collect data electronically & automatically from major retailers

• Feed all data electronically into one location

• Analyse at different jurisdictional levels as required


Features & Utility


Web-based Data Collection, Analysis and Reporting

https://www.cnphi-rcrsp.ca/cnph

“Canadian Early Warning System” (CEWS)


Currently:

• 6 (almost 7!) major retailers providing data for all of their locations across Canada;

(~2200 locations representing ~50% of all major retailers’ pharmacies)

• PHAC providing wkly reports/alerts to pilot PHUs

• Pilot PHU users have access to web-based monitoring (via CNPHI-CEWS)

• Interaction with PH officials and Pharmacy reps


DATA:

• UPC level daily sales volumes by pharmacy location

• Adult and Paediatric:

anti-diarrhoeal, anti-nauseant, rehydration;

cough and cold products, vaporisers, thermometers


TO DO:

• Enlist more retailers

• Evaluate on-line system by PH & pharmacy officials in next year


Challenges…and Advantages

What’s the Word at the Public Health Region Water Cooler?


“OTC data are not that useful for primary detection.”

“ER visit data are better at earlier detection of disease outbreaks.”

“OTC data are non-specific.”

“Rural areas are poorly represented (if at all) by OTC data.“


HOWEVER,…

In combination with other information…

GBHU Cryptosporidiosis Cases 2006 by Week of Onset

0

1

2

3

4

5

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39

Week in 2006

# of C

ases

ECADS GI Alert 2 days May 14/15

OTC Sales Alert May 27

OTC Sales Alert Jun 4

ECADS GI Alert 4 days J 14-17

GBHU Alert to EDs re-GI increase - do stool tests J 16

OTC Sales Alerts Aug 2-12

OTC Sales Alert Aug 20-Sept 9

GBHU notifies area HUs & MOHLTC of increase CIOS Alert

posted

With thanks: Dr. Hazel Lynn, Alanna Leffley Grey Bruce Health,

ECADS research team - OTTAWA


A final comment…The very process of investigating OTC sales-based

surveillance has increased the level of communication between pharmacy and public health officials.


Acknowledgements:Public Health Agency of Canada (esp. P Muchaal, J Aramini, S Mukhi)

Walkerton area pharmacists (esp. K. Brown)

Public Health Units: Grey-Bruce, Wellington-Dufferin-Guelph, Kingston Frontenac Lennox & Addington, Waterloo Region,

City of Hamilton, Winnipeg Region)

CRTI funding for CNPHI

PharmaPlus and Rexall (KATZ Group Canada Ltd), Shoppers Drug Mart, Wal-Mart, Loblaw, London Drugs, Safeway

Canadian Association of Chain Drug Stores (CACDS)

University of Guelph

ECADS and the Grey Bruce Health Unit

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Foodborne, Waterborne and Zoonotic Infections Division