Extended Data Table 1.
Characteristics of the study cohort of children affiliated to FONASA, overall, with laboratory-confirmed COVID-19 and the proportion receiving one or more doses of COVID-19 vaccines, 6 December 2021 through 26 February 2022a
| Vaccinated | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| COVID-19 | Unvaccinated | One dose | Two doses | |||||||
| Characteristic | No. | Col. % | No. | Row % | No. | Row % | No. | Row % | No. | Row % |
| Total | 490,694 | 100 | 14,512 | 3.0 | 189,523 | 38.6 | 106,744 | 21.8 | 194,427 | 39.6 |
| Sex | ||||||||||
| Female | 241,429 | 49 | 6,815 | 2.8 | 90,586 | 38 | 52,593 | 22 | 98,250 | 41 |
| Male | 249,265 | 51 | 7,697 | 3.1 | 98,937 | 40 | 54,151 | 22 | 96,177 | 39 |
| Cohort location | ||||||||||
| Arica | 7,488 | 1.5 | 304 | 4.1 | 3,739 | 50 | 1,774 | 24 | 1,975 | 26 |
| Tarapacá | 11,165 | 2.3 | 259 | 2.3 | 5,407 | 48 | 2,592 | 23 | 3,166 | 28 |
| Antofagasta | 16,652 | 3.4 | 350 | 2.1 | 6,440 | 39 | 3,937 | 24 | 6,275 | 38 |
| Atacama | 8,687 | 1.8 | 409 | 4.7 | 3,514 | 40 | 2,118 | 24 | 3,055 | 35 |
| Coquimbo | 24,079 | 4.9 | 733 | 3.0 | 9,909 | 41 | 5,578 | 23 | 8,592 | 36 |
| Valparaíso | 49,595 | 10.0 | 1,464 | 3.0 | 18,427 | 37 | 10,662 | 21 | 20,506 | 41 |
| Metropolitana | 181,781 | 37.0 | 3,925 | 2.2 | 67,537 | 37 | 38,348 | 21 | 75,896 | 42 |
| LB O’Higgins | 27,870 | 5.7 | 757 | 2.7 | 8,518 | 31 | 5,820 | 21 | 13,532 | 49 |
| Maule | 33,352 | 6.8 | 1,272 | 3.8 | 10,091 | 30 | 7,409 | 21 | 15,852 | 47 |
| Ñuble | 14,040 | 2.9 | 663 | 4.7 | 4,909 | 35 | 3,223 | 22 | 5,908 | 42 |
| Biobío | 43,107 | 8.8 | 1,857 | 4.3 | 16,564 | 38 | 10,090 | 23 | 16,453 | 38 |
| Araucanía | 31,150 | 6.3 | 951 | 3.1 | 14,083 | 45 | 6,460 | 23 | 10,607 | 34 |
| Los Ríos | 10,837 | 2.2 | 513 | 4.7 | 4,894 | 45 | 2,332 | 21 | 3,611 | 33 |
| Los Lagos | 24,781 | 5.1 | 777 | 3.1 | 12,878 | 52 | 5,026 | 22 | 6,877 | 28 |
| Aysén | 2,427 | 0.5 | 119 | 4.9 | 1,073 | 44 | 549 | 23 | 805 | 33 |
| Magallanes | 3,683 | 0.7 | 159 | 4.3 | 1,540 | 42 | 826 | 22 | 1,317 | 36 |
| Age group | ||||||||||
| 3 years | 161,379 | 33 | 4,816 | 3.0 | 76,259 | 47 | 33,096 | 21 | 52,024 | 32 |
| 4 years | 160,829 | 33 | 4,581 | 2.8 | 60,282 | 37 | 35,919 | 22 | 64,628 | 40 |
| 5 years | 168,486 | 34 | 5,115 | 3.0 | 52,982 | 31 | 37,729 | 22 | 77,775 | 46 |
| Comorbidities b | ||||||||||
| None | 445,074 | 90.7 | 12,669 | 2.8 | 174,187 | 39 | 96,221 | 22 | 174,666 | 39 |
| ≥1 | 45,620 | 9.3 | 1,843 | 4.0 | 15,336 | 34 | 10,523 | 23 | 19,761 | 43 |
| Nationality | ||||||||||
| Chilean | 484,715 | 98.8 | 14,404 | 3.0 | 186,988 | 39 | 105,613 | 22 | 192,114 | 39.6 |
| Non-Chilean | 5,979 | 1.2 | 108 | 1.8 | 2,535 | 42 | 1,131 | 19 | 2,313 | 38.7 |
aOn 6 September 2021, the Public Health Institute of Chile authorized the emergency use of CoronaVac for children aged 6 years and older and, on 25 November 2021, extended the age range to children starting at 3 years of age. The first children aged 3–5 years were vaccinated on 6 December 2021, prioritizing immunocompromised children and those with comorbidities, including chronic kidney disease, diabetes mellitus types 1 and 2, cancer, congenital heart disease and HIV. Our study cohort included children 3–5 years of age affiliated to FONASA, the national public health insurance program in Chile. We excluded children with probable or confirmed SARS-CoV-2 infection before 6 December 2021. The model also included health insurance category (a proxy of household income) and location (16 regions). We found statistically significant differences (P < 0.001) between patients with COVID-19 and the vaccinated and unvaccinated groups by sex, age group, comorbidities, nationality, region of residence and health insurance category.
bCoexisting conditions included chronic kidney disease, diabetes mellitus types 1 and 2, cancer, congenital heart disease, HIV, epilepsy, hemophilia, asthma, cystic fibrosis, juvenile idiopathic arthritis and systemic lupus erythematosus (see also Supplementary Table 2).