Volumen 7, Nº 12, junio - noviembre 2023, pp. 73-78
Escobar Segovia. Clinical recovery me for Sars-Cov-2 Infecon.
73
Clinical recovery me for Sars-Cov-2 Infecon in healthcare
workers with full and booster vaccinaon
Tiempo de recuperación clínica de la infección por Sars-Cov-2 en
trabajadores del sector sanitario con vacunación completa y de refuerzo
Abstract
The increase of infecons at the end of 2021 and January 2022 due to the Omicron variant in Ecuador, raises doubts
regarding the eecveness of booster vaccinaon, which quesons the protecon provided by booster vaccinaon
and how oen to apply it. A sample of 419 cases is taken and compared with the personnel that have complete
(58% with third dose) and incomplete (42%) immunizaon schedules as of December 2021 and January 2022, and
the me of symptomac recovery aer SARS infecon is determined aerwards. The results show no dierence
in the recovery me in paents within the two groups and similar symptoms were observed. It is concluded that,
given the results, there is no evidence of the need for a third dose in general, but rather, it would be reasonable to
focus the eorts of a second booster only in specic vulnerable populaons, thus avoiding unnecessary adverse
eects that are becoming more frequent, and even allowing the exisng vaccines available in countries where they
are really needed.
Keywords: booster; Covid-19; healthcare workers; SARS-CoV-2; vaccines.
Resumen
El incremento de infecciones a nales de 2021 y enero de 2022 por la variante Ómicron en Ecuador, plantea dudas
sobre la ecacia de la vacunación de refuerzo, lo que cuesona la protección que proporciona la vacunación de
refuerzo y la frecuencia con la que debe aplicarse. Se toma una muestra de 419 casos y se compara con el personal
que ene calendarios de vacunación completo (58% con tercera dosis) e incompleto (42%) a diciembre de 2021 y
enero de 2022, y se determina posteriormente el empo de recuperación sintomáca tras la infección por SRAS.
Los resultados no muestran diferencias en el empo de recuperación de los pacientes de los dos grupos y se obser-
van síntomas similares. Se concluye que, a la vista de los resultados, no hay evidencia de la necesidad de una ter-
cera dosis en general, sino que sería razonable centrar los esfuerzos de un segundo refuerzo sólo en poblaciones
especícas vulnerables, evitando así efectos adversos innecesarios cada vez más frecuentes, e incluso permiendo
disponer de las vacunas existentes en países donde realmente se necesitan.
Palabras clave: refuerzo; Covid-19; personal sanitario; SARS-CoV-2; vacunas.
Ana María Espinoza-Centeno
1
; Darío Alcívar-Zambrano
2
; Kenny Escobar-Segovia
3
(Recibido: febrero 27, Aceptado: mayo 23, 2023)
hps://doi.org/10.29076/issn.2602-8360vol7iss12.2023pp73-78p
1 Universidad Espíritu Santo, Samborondón, Ecuador. Email: amespinozac@uees.edu.ec. ORCID: hps://orcid.org/0000-0001-
5373-7151
2 Universidad Espíritu Santo, Samborondón, Ecuador. Email: dalcivarz@uees.edu.ec. ORCID: hps://orcid.org/0000-0002-5498-
6886
3 Escuela Superior Politécnica del Litoral, ESPOL, Guayaquil, Ecuador. Email: kescobar@espol.edu.ec. ORCID: hps://orcid.
org/0000-0003-1278-7640
74
Volumen 7, Nº 12, junio - noviembre 2023, pp. 73-78
Escobar Segovia. Clinical recovery me for Sars-Cov-2 Infecon.
INTRODUCTION
Since its emergence in December 2019,
the Covid-19 has presented many clinical
manifestaons, where most paents
(85%) report only mild symptoms (1) and a
considerable amount of acute and chronic illness
(15%), pung enormous pressure on healthcare
systems worldwide (2) with early detecon
being crical. However, despite improvements
in screening tests and vaccine ecacy, genec
variants, potenal reinfecons, and lack of
evidence on long-term immune responses
to SARS-CoV-2 (3), threaten the progress of
both protecons from primary infecon (2),
and therefore, a public health system eort
is required to maintain biosecurity measures,
accelerate vaccinaon worldwide, and thus
prevent morbidity and mortality from Covid-19
(3).
Most licensed Covid-19 vaccines use a two-dose
(homologous) strategy (primary and booster),
except for the single-dose Ad26-Cov2.S
adenovirus vector vaccine (Janssen). Evidence
suggests (4) that the immune response following
the full (two-dose) schedule in persons infected
before vaccinaon (natural immunity) may be
like or even stronger than that of persons not
exposed to the full schedule (5), so the general
strategy of two doses and even a third booster
has been quesoned.
At the same me, people working in high-risk
sengs (e.g. health care workers) are eligible
for a booster vaccinaon (in countries such as
the USA, UK, Germany, and Italy), however,
the ecacy of the third dose has not been
demonstrated in studies of 16–39-year age
groups (6), but it has been in those aged 40-
69 years who presented reduced rates of
hospital admission, severe illness and death
(7), corroborang that the dierence is more
due to the characteriscs of specialized cases.
Likewise, in a study in 2020 of a hospital in
Guayaquil, a similar trend was observed for
both hospital health personnel and the non-
hospital populaon, concluding that the spread
of this disease is linked to the social behavior of
people in their socio-family environment and
the relaxaon of biosecurity measures (8) and
not to work acvity (high-risk personnel).
On the other hand, in relaon to SARS-
COV-2 variants, the rst case of Omicron was
conrmed on November 11, 2021, in Botswana,
South Africa and currently (2022) it is the
predominant variant worldwide due to its high
transmission capacity (9). In the case of Ecuador,
on December 27, the Ministry of Public Health
(MPH) conrmed that the Omicron variant
was already community-acquired; therefore,
the present study aims to determine whether
there is a dierence in the days of recovery from
Covid-19 infecon between workers who had a
booster dose (3 doses) and those who had only
a full dose (2 doses).
METHODOLOGY
Descripve study, mixed observaonal
retrospecve, study populaon, health workers
of a hospital in Guayaquil-Ecuador (n=1247)
of which 419 tested posive in January 2022.
The "RT-PCR for Covid-19" and "An- SARS-
CoV-2 nasopharyngeal Covid-19 angen" tests
were used to determine the posive status of
the disease. In addion, the number of days of
symptomac evoluon of hospital personnel
is recorded to determine medical discharge
according to the absence of symptoms.
A database was created with the following
informaon: type of posion (administrave-
hospital); grouped posion (doctor, nurse,
technologists, etc.); age, sex, previous history
of covid-19 determined by "RT-PCR" test and
vaccinaon card of the last dose veried in the
MPH system (hps://cercados-vacunas.msp.
gob.ec/), type of vaccine and date of applicaon
of the last dose.
The data were analyzed in SPSS, obtaining
frequency and percentage of the dierent
variables, in addion to the relaonship
between a quantave variable (symptomac
count of Covid-19 days) and a qualitave variable
(complete vaccinaon and booster vaccinaon)
to determine whether there is a dierence in
symptomac recovery as a protecve factor for
the vaccinaon variables.
The Student's T-test for independent samples
was used, establishing as null hypothesis that
Volumen 7, Nº 12, junio - noviembre 2023, pp. 73-78
Escobar Segovia. Clinical recovery me for Sars-Cov-2 Infecon.
75
there is no dierence between recovery mes
with complete or booster vaccinaon, with a
condence level of 95%.
RESULTS
Between December 2021 and January 2022,
There was a higher number of infecons in the
populaon with no history of previous Covid-19
(20%), compared to those with a history of
previous Covid-19 (14%).
In the case of complete and booster vaccinaon
we obtained a slightly higher percentage in
that populaon that had the 1st booster (18%)
against Covid-19, compared to those who had
complete vaccinaon (15%). Table 1.
The results show that of the 419 cases of SARS-
CoV-2 aributable to the Omicron variant, 55%
of the posive cases had 3 doses of vaccine with
a me of applicaon of the third dose greater
than 15 days, 92% of them, only 8% with a me
of applicaon less than 15 days prior to the
posive result for SARS-CoV-2, and only 0.5%
of the infected personnel had only one dose of
vaccinaon (Figure 3).
A dierence in days of recovery can be observed
between the populaon with complete and
incomplete vaccinaon; however, when
Student's t-test was performed, no dierences
were found (p value => .05). This is due to the
there was an increase in the number of Covid-19
cases in healthcare workers with upper airway
symptoms without pulmonary involvement
aributable to the Omicron variant, with a total
of 419 people infected, represenng 34% of the
total study populaon (n=1247).
Figure 1. Presentation of Covid-19, 2022 cases in vaccinated health care personnel.
Figure 2. Difference in symptomatic recovery in workers
with complete and incomplete vaccination. Simple box
diagramo of the medical recovery days for vacccination
against Covid-19
Table 1. Covid-19 presentation in January 2022 in
healthcare personnel with a history of previous Covid
and booster vaccination.
%: Percentage
Covid-19 january 2022
Yes Not
Count % Count %
History of Covid-19 Yes 171 14 415 33
Not 248 20 413 33
Boost Vaccinaon Yes 229 18 499 40
Not 190 15 329 26
fact that 99.3% of the populaon under study
was fully vaccinated and only two cases with
incomplete vaccinaon presented Covid-19
in January, which is not a sucient sample to
determine the existence of dierences (Figure
2).
76
Volumen 7, Nº 12, junio - noviembre 2023, pp. 73-78
Escobar Segovia. Clinical recovery me for Sars-Cov-2 Infecon.
Figure 3. Simple error bar, mean of days of medical
recovery with booster vaccination
The T-test for independent samples indicates
that the null hypothesis is accepted, i.e., there
is no dierence in the average number of
days of symptomac symptoms between the
DISCUSSION
Some studies have demonstrated persistence of
anbodies in healthcare personnel for more than
six months aer a primary infecon, a nding that
may conrm long-term protecon against SARS-
CoV-2infecon. (10) Thus, a history of previous
illness generates natural immune protecon,
in addion to the acquired protecon aorded
by a complete vaccinaon schedule. Where in a
fully vaccinated hospital populaon presenng
with Covid-19, the majority presented with mild
symptoms with uncomplicated recovery. (11) In
addion, having natural anbodies to Covid-19
is a very important factor.
In addion, having natural and acquired
anbodies did not generate a complete barrier
to a new SARS-Cov-2 infecon, and it was
proven in the study populaon that the spread
of this disease is linked to the social behavior of
people in their socio-familial environment and
relaxaon of biosecurity measures; Therefore,
it is possible that health personnel, despite
the occupaonal risk of Covid-19, can remain
Table 2. Test of independent samples
t test for equality of means
t gl Sig. Dierence of
means
Medical
recovery days Equal variances are assumed -0.242 547 0.809 -0.062
Variances are not assumed to be equal -0.240 512.348 0.811 -0.062
populaon with complete vaccinaon and the
booster vaccinaon. (t= -0.242; gl: 547; p>0.05)
Table 2.
undefeated from massive contagion, as long as
they comply with all biosecurity measures, are
provided with personal protecve equipment
and evaluated on the correct use of the same.
(8)
The present study has some limitaons, one
of them being the sequencing of the Covid-19
test to determine the type of variable that
predominated at the end of 2021 and January
2022 in the hospital populaon. However,
epidemiological studies in Ecuador show the
predominance of the omicron variant between
the end of 2021 and the beginning of 2022 (6).
Moreover, it is known that clinical symptoms
were mild to moderate, demonstrang that
even three doses of mRNA vaccines were not
sucient to prevent infecons and symptomac
disease with the Omicron variant. However,
protecon against severe disease is likely to
remain intact in persons who have received full
or booster doses (6).
Vaccinaon in the health care workers in this
study mostly presents two doses; only a low
Volumen 7, Nº 12, junio - noviembre 2023, pp. 73-78
Escobar Segovia. Clinical recovery me for Sars-Cov-2 Infecon.
77
number had incomplete vaccinaon and only
two of them were infected in January 2022, so
the dierence in symptomac recovery days
could not be demonstrated because of the
low number; however, these workers required
hospitalizaon for Covid-19 of moderate
characteriscs and pulmonary involvement.
Vaccinaon against Covid-19 has been available
for more than a year. It can be observed in
most of the underdeveloped countries a low
vaccinated populaon who represent a higher
risk before the appearance of new variants,
such as omicron which was idened for the
rst me in South Africa on November 9, 2021.
African countries have the lowest vaccinaon
rates compared to other countries (11).
The boosters have already sparked a debate on
issues of equity and the priorizaon of limited
vaccine resources. Sciensts are concerned that
rich countries will rush to provide more Omicron
boosters, which will exacerbate the global
vaccine imbalance that many health researchers
believe contributed to the emergence and rapid
spread of Omicron (6).
CONCLUSIONS
This study demonstrates that although a large
percentage of the hospital populaon with a
booster dose and a prior history of Covid-19 did
not provide a protecve barrier to re-infecon,
there was no dierence with respect to the
severity of symptoms, which is determined by
recovery me following SARS-Cov-2 infecon in
healthcare personnel who had a booster dose (3
doses). Furthermore, there was no dierence in
the severity of symptoms, which is determined
by the recovery me following SARS-Cov-2
infecon in healthcare personnel who had a
booster dose (3 doses) vs. full vaccinaon (2
doses).
This rearms even more that contagion is
linked to social behavior and relaxaon of
security measures, which unl now has been
the best protecon mechanism and should be
maintained unl the pandemic connues.
As well as establishing equitable vaccinaon
worldwide, because it is in those countries
that do not have immune coverage, where
new mutaons of the virus are being born.
Therefore, it would be reasonable for eorts
to be administered only to specic populaons
where the evidence shows that they are likely to
be needed.
On a global scale, this would avoid millions of
unnecessary adverse eects that are increasingly
common and, more importantly, make these
vaccines available to the countries where they
are most needed. A pandemic, aer all, requires
a global strategy.
REFERENCES
1. PAHO/WHO | Pan American Health
Organization/World Health Organization.
COVID-19 Situation Reports. Disponible
en https://www.paho.org/en/covid-19-
situation-reports
2. Milne G, Hames T, Scotton C, Gent N,
Johnsen A, Anderson RM, et al. Does
infection with or vaccination against
SARS-CoV-2 lead to lasting immunity?
Lancet Respir Med. 2021; 9(12):1450–
1466. https://doi.org/10.1016/S2213-
2600(21)00407-0.
3. Townsend JP, Hassler HB, Wang Z, Miura
S, Singh J, Kumar S, et al. The durability
of immunity against reinfection by SARS-
CoV-2: a comparative evolutionary study.
Lancet Microbe. 2021; 2(12): e666–
e675. https://doi.org/10.1016/S2666-
5247(21)00219-6.
4. Bhattacharya A, Ranjan P, Ghosh T,
Agarwal H, Seth S, Maher GT, et al.
Evaluation of the dose-effect association
between the number of doses and
duration since the last dose of COVID-19
vaccine, and its efficacy in preventing the
disease and reducing disease severity: A
single centre, cross-sectional analytical
study from India. Diabetes & Metabolic
Syndrome: Clinical Research & Reviews.
2021; 15(5):102238. https://doi.
org/10.1016/j.dsx.2021.102238.
5. Milne G, Hames T, Scotton C, Gent N,
Johnsen A, Anderson RM, Ward T. Does
infection with or vaccination against SARS-
CoV-2 lead to lasting immunity? Lancet
78
Volumen 7, Nº 12, junio - noviembre 2023, pp. 73-78
Escobar Segovia. Clinical recovery me for Sars-Cov-2 Infecon.
Respir Med. 2021; 9(12):1450-1466. doi:
10.1016/S2213-2600(21)00407-0.
6. Alba JMG, Pérez-Martínez Z, Boga
JA, Rojo-Alba S, de Oña JG, Alvarez-
Argüelles ME, et al. Emergence of
new SARS-CoV2 Omicron variants
after the change of surveillance and
control strategy. Microorganisms. 2022;
10(10):1954. http://dx.doi.org/10.3390/
microorganisms10101954
7. Cirillo N. Do health-care workers need
a COVID-19 vaccine booster? Lancet
Infect Dis. 2022; 22:20. https://doi.
org/10.1016/S1473-3099(21)00782-9.
8. Alcívar Zambrano D, Espinoza Centeno
A, Escobar Segovia KF. Impacto de
la pandemia por SARS-CoV-2 en los
trabajadores de un Hospital de Guayaquil
en el año 2020. Rev San Gregor. 2022;
1:63–73. https://doi.org/10.36097/rsan.
v0i49.1958
9. GISAID. Tracking of hCoV-19 Variants.
Global Initiative on Sharing All Influenza
Data. Disponible en: https://gisaid.org/
hcov19-variants/
10. Al-Naamani K, Al-Jahdhami I, Al-Tamtami
W, Al-Amri K, Al-Khabori M, Sinani SA, et al.
Prevalence and persistence of SARS-CoV2
antibodies among healthcare workers in
Oman. Journal of Infectionand Public
Health. 2021; 14(11):1578–1584. https://
doi.org/10.1016/j.jiph.2021.09.006
11. Chau NVV, Ngoc NM, Nguyet LA,
Quang VM, Ny NTH, Khoa DB, et al. An
observational study of breakthrough
SARS-CoV-2 Delta variant infections
among vaccinated healthcare workers
in Vietnam. EClinicalMedicine 2021;
41:101143. https://doi.org/10.1016/j.
eclinm.2021.101143
