medRxiv preprint doi: https://doi.org/10.1101/2021.07.01.21259330; this version posted July 6, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. All rights reserved. No reuse allowed without permission.
Indirect impact on number of admitted children with COVID-19 in the first three months of emergency use of two vaccines, in Rio de Janeiro, Brazil
Authors: Fonseca CGB 1, Costa ALTG 1, Esteves MDM 1, de Carvalho BRR 1, Souza
CV 2 , Teixeira CH 2, Araujo da Silva, AR 1,2
1- Universidade Federal Fluminense
2- Infection Control Committee- Prontobaby-Group
Abstract:
Introduction: Since January 19, 2021, two vaccines against SARS-COV-2 are
available in Brazil for emergency use for selected groups, not including children.
Aim: To describe indirect impact on the number of hospitalized children with COVID-
19 in the first three months after beginning of emergency use of two vaccines.
Methods: A retrospective study was conducted in children (0-18 years), admitted in
two pediatric hospitals of Rio de Janeiro city, between January and April 2021 with
confirmed COVID-19 by reverse transcription polymerase chain reaction or serological
tests. Number of cases, clinical signs, symptoms and outcomes were compared with the
first wave of disease (April- June 2020). A p value of less than .05 were considered was
significant.
Results: The number of total admitted patients (with all diseases) were 1097 in 2020
period, being 46 (4.2%) of them with confirmed COVID-19, and 2187 in the 2021
period, with 47 (2.1%) cases (p=0.006). Predominant respiratory symptoms were
present in 29/46 (63%) as the main presentation in 2020 patients and 37/47 (78.7%) in
2021 children (p=0.09). The main symptoms were fever, cough and dyspnoea in both
periods. The median of lenght of stay after diagnosis were 4 days in 2020 and 2021 (
p=0.9). Just one patient died in 2021.
NOTE: This preprint reports new research that has not been certified by peer review and should not be used to guide clinical practice. medRxiv preprint doi: https://doi.org/10.1101/2021.07.01.21259330; this version posted July 6, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. All rights reserved. No reuse allowed without permission.
Conclusion: There was reduction of relative percentage of admitted confirmed pediatric
cases in the the first three months of emergency use of two vaccines against SARS-
COV-2, but it’s uncertain to atribute this finding to vaccination due to high circulation
of the virus in the city.
Key-words: COVID 19, pediatrics, clinical manifestations, hospitalization, vaccine.
Introduction:
Until June 18, 2021 more than 177 million of people were diagnosed with
COVID-19 in all countries, with at least 3,8 million of deaths. 1 The pandemic of
SARS-COV-2 stills in progress in May 2021, despite global efforts to reduce impact of
disease around the world. 1
Several non-pharmaceutical interventions (NPIs) were implemented wordwide
to mitigate the spread of SARS-CoV-2, considering absence of vaccine or effective
antiviral in the first year of pandemics and includes closure of educational institutions,
national lockdown, mass gathering cancellation, border restriction, quarantine and
others. 2,3
After massive research simultaneously conducted in different countries,
companies and universities, the first vaccine (Pfizer–BioNTech) for COVID-19
prevention was approved in early December 2020, by United Kingdom's Medicines and
Healthcare products Regulatory Agency (MHRA) for selected groups. 4 Since then,
other vaccines were approved for different countries including Brazil, but effects of
reducing cases needs to be studied, including subgroups not included in vaccination as
children. medRxiv preprint doi: https://doi.org/10.1101/2021.07.01.21259330; this version posted July 6, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. All rights reserved. No reuse allowed without permission.
Considering the use of two vaccines for COVID-19 prevention since January
2021, in Brazil, our aim is to describe indirect impact on the number of hospitalized
children with COVID-19 in the first three months after beginning of emergency use of
two vaccines.
Methods
Study design and setting:
We conducted a retrospective cohort study in two pediatric hospitals in Rio de
Janeiro, city, Brazil. Both hospitals are private units destined exclusively to pediatric
patients.
Unit 1 is a 135-bed hospital located at North zone of the city, that receives
clinical and surgical patients referred from its own emergency and from other services.
Unit 2 is a 39-bed hospital, located at South zone of the city, with the same profile of
unit 1.
Period of the study:
Two periods were analysed: the first one comprised the first day of Brazilian
epidemiological week 15 (April 5, 2020) and the last day of epidemiological week 27
(July 4, 2020). This period corresponds to the first wave of COVID-19, according to the
historical series of confirmed cases attending in both hospitals. The second period
comprises the first day of epidemiological week 3 of 2021 (January 17th) and last day of
epidemiological week 15 of the same year (April 17th). This period corresponds to the
first three months after beginning of vaccination in Rio de Janeiro city.
In both periods studied, higher number of COVID-19 cases were detected in the
city. 5 medRxiv preprint doi: https://doi.org/10.1101/2021.07.01.21259330; this version posted July 6, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. All rights reserved. No reuse allowed without permission.
Inclusion and exclusion criteria:
All patients admitted with COVID-19 in both hospitals were included in
analysis. Children admitted but transferred to the other hospitals within the first 24h
were excluded.
COVID-19 vaccines available and priority groups:
Two vaccines were available by emergency use in Brazil, by The Brazilian
Health Regulatory Agency (ANVISA): CoronaVac ® and Oxford/AstraZeneca ® and
one for definitive use (Pfizer- BioNTech ®), at the end of April 2021. 6 The first doses
of vaccines were administered in Rio de Janeiro, in January 20, 2021, but until the end
of April 2021, Pfizer- BioNTech vaccine was not available for population and not
included in the current analysis
Until April 14 2021, the following groups received at least one dose of vaccine:
persons older than 63 years and healthcare workers (all ages) with direct contact with
patients. No vaccine was available for children
Diagnostic of COVID-19 infection:
A patient was considered as a confirmed case of COVID-19 in the presence of
positive polymerase chain reaction (PCR), positive IgM serology or positive antigen
reaction. For epidemiological analyses, we considered date of beginning of the
symptoms.
Data source and statistical analysis:
The two periods were analysed regarding the following variables: Total number
of admitted patients (with all diseases), total number of admitted patients with
confirmed COVID-19, the main clinical symptoms present on admission and number of
deaths medRxiv preprint doi: https://doi.org/10.1101/2021.07.01.21259330; this version posted July 6, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. All rights reserved. No reuse allowed without permission.
A descriptive analysis was performed using Microsoft Excel. When appropriate,
we used Chi square test for categorical variables and Mann–Whitney U test for
continuous variables. A value of p less than .05 were considered as statistical
significant.
Ethical aspects:
The study was submitted and approved by Ethics Committee of Faculty of
Medicine (Universidade Federal Fluminense) and Prontobaby Group, under number
4.100.232 dated from June 20, 2020.
Results:
In the first period analysed (April 5,2020- July 4, 2020), 1097 children were
admitted, being 46 (4.2%) with confirmed COVID-19 infection. Considering the second
of period of analysis (January 17, 2021- April 17, 2021), 2187 children were admitted,
with 47 (2.1%) confirmed COVID-19 infection (p=0.0006). Demographic data about
presentation of symptoms and outcomes are presented in table 1
Table 1- Demographic data of pediatric patients admitted with COVID-19 in the first
wave and first 12 weeks after beginning of emergency vaccine in Rio de Janeiro, city
Confimed cases first Confirmed cases of first P
wave 12 weeks after beginning value
N= 46 of emergency vaccination
N=47
Male gender (%) 28 (60.8) 25 (53.2) 0.46
Median age ( in months) 86.5 41 0.12
Clinical presentation medRxiv preprint doi: https://doi.org/10.1101/2021.07.01.21259330; this version posted July 6, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. All rights reserved. No reuse allowed without permission.
Predominant respiratory 29 (63) 37 (78.7) 0.09
symptoms (%)
Predominant non- 17 (37) 10 (21.2)
respiratory symptoms (%)
Outcomes
Discharged 46 (100) 46 ( 97.9) 0.32
Dead 0 1 ( 2.1)
Lenght of stay after 4 4 0.90
diagnosis (median in
days)
The main symptoms in the first wave patients were fever in 36/46 (78.3%) of
patients, dyspnoea in 24/46 (52.2%) and cough in 23/46 (50%). In the second period of
analysis the most common symptoms were fever in 35/47 (74.5%) children, cough in
34/47 (72.3%) and dyspnoea in 25/47 (53.2%) patients
The graph one shows the cases since the first one diagnosed in 2020 until April
17, 2021, considering epidemiological weeks of Brazil surveillance
Graph 1- Number of admitted pediatric confirmed COVID cases considering
epidemiological weeks of Brazil surveillance (2020-2021) medRxiv preprint doi: https://doi.org/10.1101/2021.07.01.21259330; this version posted July 6, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. All rights reserved. No reuse allowed without permission.
10 First Beginning of vaccination 9 wave
8
7
6
5
4
3
2
1
0 1357911131517192123252729313335373941434547495153246810121416
Nº of cases
Discussion:
According to the last Brazilian Epidemiological Bulletin relative to COVID data,
children represent around 1.4% of acute respiratory distress syndrome (ARDS) cases
and 0.35 % of deaths atributted to COVID ARDS, respectively during 2021 year in
Brazil. But, despite of relative few number of cases and deaths, the pandemic still
uncontrolled in the whole country. 7
Starting in end of 2020, systematic vaccination of selected groups is increasing
in the world as a strategy to limit the spread of SARS-COV-2 in addition to NPIs. 4
Brazil began his vaccination program in January 2021, for elderly people and healthcare
personnel and it’s possible that some indirect impact about reduction of pediatric cases
could be verified in children, due to family composition in Brazil, where grandparents
participate of children care. 8
Considering the two periods of analysis in our study, number of admitted
children due to the all causes increased in 2021 compared with previous year. We could
atribute this finding to the restriction of circulation in Rio de Janeiro in the 2020 year medRxiv preprint doi: https://doi.org/10.1101/2021.07.01.21259330; this version posted July 6, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. All rights reserved. No reuse allowed without permission.
and flexibilization of coletive rules in the second period. Other countries as Singapore
and Canada also experienced reduction of visities to emergency department and
hospitalizations. 9,10
COVID-19 is a mild/severe infection in children and we verified that the main
symptoms of disease (fever, cough and dyspnoea) were similar in both years studied,
confirming that disease is a predominant illness of respiratory tract, with some cases of
unsual presentation as multisystem inflammatory syndrome (MIS-C) and just one death.
A recent meta-analysis about COVID-19 concluded that children and/or adolescents
tend to have a mild COVID-19 course with a good prognosis when compared to adults.
11
The absolute number of COVID-19 cases were similar in both periods analysed,
but when we compared relative percentage of cases, considering total number of
admitted patients, there was a statistically significant reduction of confirmed cases.
Vaccination against SARS-COV-2 is in different stages around the world and
countries that have been started his programm earlier, covering higher percentage of
population, obtained promising results. One of the first reports about effects of
vaccination verified a larger and earlier decrease in COVID-19 cases and hospitalization
in individuals older than 60 years, followed by younger age groups. 12 In United
Kingdom, a model suggests substantial reductions in hospital and intensive care units
admissions would not occur until three/four months after beginning of COVID-19
vaccination in that country. 13
The positive impact about relative percentage of admitted children during the
study period could be na initial marker of vaccination effects, but natural decrease of
number of cases, considering a possible seasonality of the vírus, could be not
foreclosed. medRxiv preprint doi: https://doi.org/10.1101/2021.07.01.21259330; this version posted July 6, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. All rights reserved. No reuse allowed without permission.
Our study has some limitations. The first one is that our data showed pattern of
admissions in two pediatric hospital of the city. But considering that both hospitals are
the biggest institutions dedicated exclusively to the children care in the city, that data
could reflect the true dynamics of SARS-COV-2 circulation in the city. The second
limitation is possible influence of knowledge acquistion of pediatricians to treat
COVID-19, during the first year of pandemic, resulting in fewer relative percentage of
admitted children with COVID-19 in 2021. Despite this possibility could be not rulled
out, until the current date, no drug was approved in Brazil to avoid or reduce pediatric
COVID-19 admissions.
Conclusion:
There was reduction of relative percentage of admitted confirmed pediatric cases
in the the first three months of emergency use of two vaccines against SARS-COV-2,
but it’s uncertain to atribute this finding to vaccination due to high circulation of the
virus in the city.
Acknowlegdment:
We thank to Mario Eduardo Viana and Luisa Benigno Barbosa Araujo da Silva
for supporting this research.
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