COVID-19 in children and youth Canada, January 15–April 27, 2020

CCDR

Volume 46–5, May 7, 2020: Nosocomial infection surveillance

Update

Laboratory-confirmed COVID-19 in children and youth in Canada, January 15–April 27, 2020

Dana Paquette1, Christopher Bell1, Maxime Roy1, Lindsay Whitmore1, Andrea Currie1, Chris Archibald1, Diane MacDonald1, Jennifer Pennock1

Affiliation

1 Public Health Agency of Canada, Ottawa, ON

Correspondence

lindsay.whitmore@canada.ca

Suggested citation

Paquette D, Bell C, Roy M, Whitmore L, Currie A, Archibald C, MacDonald D, Pennock J. Laboratory-confirmed COVID-19 in children and youth in Canada, January 15–April 27, 2020. Can Commun Dis Rep 2020;46(5):121–4. https://doi.org/10.14745/ccdr.v46i05a04

Keywords: COVID-19, youth, children, Canada, surveillance

Editor’s note: This article has been submitted as a Rapid Communication to provide current information related to COVID-19 that may have immediate implications.

Abstract

Understanding the epidemiology of COVID-19 among children and youth in Canada will help to inform public health measures in settings where children gather. As of April 27, 2020, provinces and territories provided the Public Health Agency of Canada with detailed information on 24,079 cases, of which 3.9% (n=938) were younger than 20 years of age. The detection rate per 100,000 population was lower in this age group (11.9 per 100,000), compared with those aged 20–59 years (72.4 per 100,000) and 60 and older (113.6 per 100,000). The median age among those younger than 20 years of age was 13 years, and cases were distributed equally across male and female genders. Among provinces and territories with more than 100 cases, 1.6% to 9.8% of cases were younger than 20 years of age. Cases in this age group were more likely to be asymptomatic: 10.7% compared with 2.4% in those aged 20–59 years and 4.1% in those aged 60 and older. Children and youth experienced severe outcomes less often, but 2.2% (n=15/672) of cases within this age group were severe enough to require hospitalization. Based on available exposure information, 11.3% (n=59/520) of cases aged younger than 20 years had no known contact with a case. Canadian findings align with those of other countries.

Introduction

As of April 27, 2020, there were 47,327 COVID-19 cases reported in Canada. With the growth in new cases slowing, provincial, territorial and federal governments are planning how and when to ease some public health measures including the timing and parameters for reopening schools, daycares and other settings where children gather. To inform such decisions, it is important to understand the epidemiology of COVID-19 among children and youth in Canada.

Current situation

Data for this analysis were drawn from laboratory-confirmed cases reported to the Public Health Agency of Canada (PHAC) as of April 27, 2020. Of the 47,327 cases reported up to that date, detailed information was provided to PHAC for 26,876 cases. Of these, 24,723 were laboratory-confirmed and 24,079 included information on age. Among these cases, 3.9% (n=938) were younger than 20 years of age, and form the basis for this analysis.

The rate of laboratory-confirmed COVID-19 cases was lower in individuals under 20 years of age at 11.9 per 100,000Footnote 1, compared with 72.4 per 100,000 for those 20 to 59 years of age and 113.6 per 100,000 for those 60 years of age and older (p<0.001). Rates per 100,000 population were consistent (7.1–11.4 per 100,000) across finer age groups for children younger than 15 years of age, while the 15–19 years of age group had a higher rate (20.7 per 100,000) (see Table 1). This difference may be due to adolescents being more independent than younger age groups and therefore more able to seek out social contact with peersFootnote 2. It is also important to note that observed differences in rates across age groups may be due, in part, to differences in laboratory testing patterns by age.

Table 1: Age distribution among cases less than 20 years of age (N=938)
Age group (years) Frequency Rate per 100,000
n %
younger than 1 42 4.5 11.4
1–4 109 11.6 7.1
5–9 152 16.2 7.5
10–14 215 22.9 11.2
15–19 420 44.8 20.7
Total 938 100 11.9

Among the cases younger than 20 years, 50.7% were female and the median age was 13 years. The proportion of cases younger than 20 years reported daily remained fairly consistent over time on the days where cases numbered more than 100 (Figure 1), ranging from 2.1% to 6.9%. Information on exposure category was available for 55.4% (n=520/938) of cases younger than 20 years for which PHAC received more detailed information. Of these, 20.4% were exposed internationally, 9.6% were contacts of travelers from affected areas, 58.7% were contacts of cases infected in Canada and 11.3% had no known contact with cases. The younger age groups (0 to 4, 5 to 9 and 10 to 14 years) had a lower percentage of cases with no known contact with a case (8.0%, 8.3% and 9.7%, respectively) compared with the 15–19 year age group, in which 15.1% of cases had no known contact.

Figure 1: Epidemiologic curve from January 15 to April 27, by age groupFigure 1 footnote a, (N=22,973)

Figure 1: Epidemiologic curve from January 15 to April 27, by age group, (N=22,973)

Text description: Figure 1

Figure 1: Epidemiologic curve from January 15 to April 27, by age groupFigure 1 footnote a,(N=22,973)

Figure 1: Epidemiologic curve from January 15 to April 27,by age group, (N=22,973)
Episode date Age Group Total
Under 20 years (Orange) 20 years and older (Blue)
2020-01-15 0 1 1
2020-01-21 0 1 1
2020-01-22 0 2 2
2020-01-24 0 2 2
2020-01-27 0 1 1
2020-01-28 0 1 1
2020-02-01 0 2 2
2020-02-05 0 1 1
2020-02-08 0 1 1
2020-02-09 0 1 1
2020-02-10 0 2 2
2020-02-12 0 1 1
2020-02-13 0 2 2
2020-02-14 0 4 4
2020-02-15 1 1 2
2020-02-16 0 3 3
2020-02-17 0 1 1
2020-02-18 0 1 1
2020-02-19 0 1 1
2020-02-20 0 6 6
2020-02-21 1 2 3
2020-02-22 0 7 7
2020-02-23 1 9 10
2020-02-24 1 7 8
2020-02-25 0 10 10
2020-02-26 0 6 6
2020-02-27 1 11 12
2020-02-28 1 14 15
2020-02-29 1 23 24
2020-03-01 0 35 35
2020-03-02 2 32 34
2020-03-03 0 42 42
2020-03-04 3 40 43
2020-03-05 1 46 47
2020-03-06 2 50 52
2020-03-07 4 68 72
2020-03-08 1 96 97
2020-03-09 5 157 162
2020-03-10 12 183 195
2020-03-11 10 203 213
2020-03-12 8 236 244
2020-03-13 18 283 301
2020-03-14Footnote * of Table 1 8 288 296
2020-03-15 10 365 375
2020-03-16 21 472 493
2020-03-17 18 513 531
2020-03-18 21 582 603
2020-03-19 26 464 490
2020-03-20 19 584 603
2020-03-21 26 485 511
2020-03-22 25 452 477
2020-03-23 30 567 597
2020-03-24 20 505 525
2020-03-25 27 513 540
2020-03-26 26 476 502
2020-03-27 17 477 494
2020-03-28 18 445 463
2020-03-29 10 372 382
2020-03-30 23 502 525
2020-03-31 13 412 425
2020-04-01 22 512 534
2020-04-02 15 449 464
2020-04-03 23 490 513
2020-04-04 12 383 395
2020-04-05 14 390 404
2020-04-06 17 528 545
2020-04-07 22 545 567
2020-04-08 18 522 540
2020-04-09 24 605 629
2020-04-10 14 664 678
2020-04-11 14 660 674
2020-04-12 22 499 521
2020-04-13 26 874 900
2020-04-14 28 677 705
2020-04-15 36 754 790
2020-04-16Footnote of Table 1 36 651 687
2020-04-17 25 674 699
2020-04-18 21 541 562
2020-04-19 21 285 306
2020-04-20 14 407 421
2020-04-21 15 266 281
2020-04-22 10 240 250
2020-04-23 7 193 200
2020-04-24 4 140 144
2020-04-25 2 60 62
2020-04-26 0 2 2

The distribution of cases in the younger than 20 years age category varied significantly across provinces and territories (p<0.001) (see Table 2), which may reflect differences in the local epidemiology of COVID-19 across provinces and territories and/or differences in laboratory testing criteria across jurisdictions. Among the jurisdictions that reported more than 100 cases (this excludes Yukon, Northwest Territories, Nunavut and Prince Edward Island), in British Columbia, Saskatchewan, Manitoba and Ontario, 5.0% or less of all reported cases were younger than 20 years, while Alberta, Quebec, New Brunswick, Nova Scotia and Newfoundland and Labrador reported a higher proportion of cases in this age group (between 6.8% and 11.1%). At the time of this report, no outbreaks were noted in settings where children gather (e.g. daycares, schools, camps, etc.). This may be due to the early timing of schools and some daycare closures.

Table 2: Number and proportion of cases less than 20 years of age, for provinces with more than 100 cases reported (N=937)
ProvinceFootnote a of Table 2 Number and proportion of cases
n %
Ontario 328 2.2
Alberta 229 8.1
Quebec 226 7.3
Nova Scotia 85 9.8
British Columbia 25 1.6
Newfoundland and Labrador 22 8.6
Manitoba 10 4.0
New Brunswick 8 6.8
Saskatchewan 4 3.2

Information on whether cases were symptomatic or not was available for 24.7% (n=5,939/24,079) of cases for which PHAC received detailed reports. A larger proportion of asymptomatic cases (10.7%) was noted in the younger than 20 years age group, compared with 2.4% in those aged 20–59 years and 4.1% in those aged 60 and older. These proportions are likely underestimates of asymptomatic cases across all age groups, given that, during the time period in question, testing was focused on high risk populations who were symptomatic.

Symptom information was available for 24.6% (n=5,912/24,079) of cases for which PHAC received detailed information. Of those who experienced symptoms, the three most common symptoms differed across age groups. The three most common symptoms for those younger than 20 years of age were cough (57.0%), runny nose (41.2%) and headache (39.4%); compared with cough (74.2%), headache (64.3%) and pain (56.0%) for those aged 20–59 years and cough (75.1%), weakness (56.2%) and fever (51.9%) for those aged 60 and older. Other common symptoms in those younger than 20 years of age included fever (36.4%), sore throat (34.3%), weakness (31.8%) and chills (30.6%).

Severe outcomes were less likely to occur in the younger age group. Hospitalization status was available for 57.0% of all cases (n=13,723/24,079) for which PHAC received detailed information. Among individuals younger than 20 years of age, 2.2% were hospitalized, compared with 10.4% in those aged 20–59 years and 35.6% among those aged 60 and older. Among those hospitalized, in cases younger than 20 years of age, 13.3% were admitted to the Intensive Care Unit. Across all age groups, these proportions likely overestimate the true proportion of COVID-19 infections that result in severe outcomes, as individuals who experienced more severe symptoms and outcomes may have been more likely to be tested and reported than those who were asymptomatic or had only mild symptoms.

Among those younger than 20 years of age, hospitalization information was available for 71.6% (n=672/938) of cases. There were only 15 hospitalizations in this age group, among which infants younger than one year of age had a higher proportion of hospitalizations than other age groups (see Table 3). However, the numbers were small in this age group, and these results should be interpreted with caution. Within the 15 hospital admissions in cases younger than 20 years of age, two cases were admitted to the Intensive Care Unit, and both cases were younger than one year of age. No deaths were reported in individuals younger than 20 years of age as of the date of this report, based on public reporting by province and territory health officials.

Table 3: Hospitalization status for cases less than 20 years of age (N=672)
Age group (years) Hospitalized Not hospitalized
n % n %
Younger than 1 4 13.3 26 86.7
1–4 0 0 83 100
5– 9 0 0 118 100
10–14 2 1.3 153 98.7
15–19 9 3.1 277 96.9
Total 15 2.2 657 97.8

Conclusion

The data presented in this report add to our knowledge of the epidemiology of COVID-19 among children and youth. Few reports have been published to date, but based on what is available in the published literature and from surveillance reports, the Canadian findings are in line with those from other countries. Fewer cases have been reported among children and youth, compared with older age groupsFootnote 3Footnote 4Footnote 5. A higher proportion of children and youth were asymptomatic, and they experienced different symptoms than adultsFootnote 6Footnote 7Footnote 8. While less severely affectedFootnote 3Footnote 4Footnote 5, hospitalizations still occurred, including among infantsFootnote 7Footnote 9 and, as in the United States, a larger proportion of infants were hospitalized when compared with older children and youthFootnote 8.

Based on these and other findings, a significant proportion of cases among children and youth was asymptomatic. Though preliminary studies suggest children are less important sources of SARS-CoV-2 infection than adults, asymptomatic transmission has been notedFootnote 10. It will, therefore, be important to maintain key public health measures even as some controls are relaxed. Among these, behaviours such as staying home when ill, maintaining physical distancing, use of non-medical masks and frequent handwashing should continue to be encouraged in this age group to prevent transmission. As well, since higher rates of confirmed infection were observed in those aged 15–19 years, additional efforts to educate and reinforce public health preventative measures, such as physical distancing, may be needed to target this more independent and mobile age group.

To ensure that COVID-19 continues to be monitored in children and youth, plans are underway for enhanced surveillance of the pediatric population. Data will be available through multiple data streams in addition to province and territory case-based reporting. Enhanced surveillance will make use of existing administrative databases and surveillance systems, including the Canadian Institute for Health Information’s Discharge Abstract Database, the Canadian Nosocomial Infections Surveillance Program and the Canadian Pediatric Surveillance Program. These data streams will provide complimentary information to monitor trends in severe pediatric cases, identify risk factors associated with disease, and assess the burden of disease within this population.

Authors’ statement

  • DP — Conceptualization, original draft, review and editing
  • CB — Data curation, formal analysis, review and editing
  • MR — Data curation, formal analysis
  • LW — Review and editing
  • AC — Review and editing
  • CA — Review and editing
  • DM — Review and editing
  • JP — Review and editing

Conflict of interest

None.

Acknowledgements

Authors wish to thank provincial and territorial surveillance partners; national and provincial laboratory partners; and the Health Portfolio Operations Centre’s Surveillance Team, Public Health Agency of Canada.

Funding

This work was supported by Public Health Agency of Canada.

Report a problem or mistake on this page
Please select all that apply:

Thank you for your help!

You will not receive a reply. For enquiries, contact us.

Date modified: