Association of clinical and epidemiological characteristics with COVID-19 BNT162b2 mRNA vaccine short-term adverse reactions in healthcare workers

ABSTRACT

Introduction

The aim of the study was to investigate the prevalence and severity of adverse reactions (ARs) after immunization of healthcare workers (HCWs) with BNT162b2 vaccine and to associate them with clinical and epidemiological characteristics.

Methods

A form containing demographic and clinical data as well as ARs after both doses of the vaccine was completed, and statistical association analysis was performed.

Results

A total of 502 HCWs (females 78.3%) with mean age (±SD) 48.17 years (±12.97) participated. After the first dose, 404 (80.5%) HCWs reported at least one local AR (LAR) and 366 (72.9%) after the second dose (p-value=0.004). After the first dose, 121 (24.1%) HCWs reported at least one systemic AR (SAR) and 275 (54.8%) after the second dose (p-value<0.0001).

In the logistic regression analysis, there was no association of gender or medical history of underlying disease with LARs. There was a negative association of age with the cumulative score (CS) of LARs (OR: 0.82, 95% CI: 0.69–0.96) after the first dose. Females had a positive association with CS of SARs following both doses (OR, 95% CI: 2.57, 1.39–4.73 and 2.71, 1.76–4.19, respectively). Age was negatively associated with CS of SARs (OR: 0.66, 95% CI: 0.57–0.76) after the second dose. Severe ARs included Bell’s palsy (1) and tinnitus with temporary hearing loss (1).

Conclusion

The administration of the BNT162b2 vaccine in our HCWs cohort had a good safety profile with the most common ARs being self-limited. An increasing rate of SARs following the second vaccine dose was noticed. Rare but severe possible ARs should be further investigated.

KEYWORDS:

• Healthcare worker
• biontech
• mRNA
• vaccine
• adverse reactions

1. Introduction

Since COVID-19 was designated as a pandemic at the beginning of 2020, vaccines to prevent SARS-CoV-2 infection are considered the most promising approach for pandemic control.¹ According to data from SARS-CoV and MERS-CoV vaccine studies, SARS-CoV-2 spike (S) protein is the predominant antigenic target for the development of a COVID-19 vaccine, as the virus enters the host cells after binding of the S protein to the human angiotensin-converting enzyme 2 (ACE2) receptor. Τhus, vaccination with the SARS-CoV-2 spike protein will prevent virus attachment on host cells.²

COVID-19 vaccines are being developed based on several different platforms, either with traditional approaches, such as live attenuated viruses, or with novel techniques, such as recombinant proteins and mRNA. BNT162b2 mRNA COVID-19 vaccine (BioNTech, Fosun Pharma, Pfizer) was one of the first vaccines to be licensed worldwide and was characterized by high immunogenicity and efficacy rate.³ A recent observational study from Israel with nearly 570000 BNT162b2 mRNA COVID-19 vaccinated participants demonstrate a highly effective, novel vaccine that significantly reduces the risk of critical COVID-19.⁴

Local and systemic adverse reactions (LARs and SARs) that are frequently reported include injection site pain, fatigue, headache and myalgias with increased intensity after the second dose of vaccination.⁵ These reactions usually occur within 2 days after vaccination, and the majority of them are mild or moderate in severity.⁵ Vaccine recipients aged 65 years or older generally report less frequent LARs and SARs compared to those of younger than 65 years old.⁵ However, severe ARs have rarely been reported, including anaphylaxis.⁶

Limited public data exist regarding association of LARs and SARs with demographic characteristics and medical history.^7,8 In the present study, we aimed to investigate the LARs and SARs following the first and second dose of the BNT162b2 vaccine in a cohort of healthcare workers (HCWs) and to correlate them with clinical and epidemiological parameters.

2. Materials and methods

2.1 Study design and participants

This was a prospective cohort study involving HCWs of “Aghia Sophia” Children’s Hospital in Athens, which is the largest tertiary pediatric hospital in Greece. The cohort of the study included healthcare professionals (medical doctors, nurses, technicians) and nonmedical personnel (administrative staff, cleaners, etc.) of the hospital who were vaccinated with the Pfizer/BioNTech BNT162b2 mRNA COVID-19 vaccine in January 2021.

A form containing demographic and clinical data as well as ARs after each COVID-19 vaccination dose was completed by each participant. Data included gender, age, blood type (O, A, B, AB), smoking status, body mass index (BMI; normal weight = 18.5–24.9 kg/m², overweight = 25–29.9 kg/m² and obesity ≥ 30 kg/m²), history of underlying diseases (cardiac, pulmonary, hyperlipidemia, hypertension, Type 1 diabetes mellitus, Hashimoto’s thyroiditis, rheumatoid arthritis, psoriasis, inflammatory bowel diseases, autoimmune hepatitis, allergies etc.). COVID-19-specific information was also obtained, including vaccination dates and number of doses, history of confirmed COVID-19 infection and presence of COVID-19-related symptoms.

Local as well as systemic ARs were recorded after each dose of the vaccine. A cumulative score of the most common local (0–2): injection site pain and edema or systemic (0–5+): fatigue, headache, myalgias, and arthralgias, temperature, gastrointestinal (GI) symptoms, lymphadenopathy and chills ARs were also used in the analysis.

The study was conducted in accordance with the Declaration of Helsinki, and the study protocol was approved by the scientific and bioethics committee of “Aghia Sophia” Children’s Hospital (No: 2794). Written informed consent was obtained from all participants.

2.2 Statistical methods

For the analysis, the absolute and relative frequencies (%) were used to describe the data. To investigate possible differences of LARs and SARs, preliminary comparison between 1st and 2nd dose was also performed using Chi-Square test. To study a possible association of the study variables with any of the different types of LARs and SARs, the data were modeled through multiple logistic regression for the binary reactions and ordinal logistic regression for the multilevel scores. Gender (female vs male), age (in 10 years increment), BMI (1 category more), underlying disease (yes vs no), and smoking (yes vs no) were the predictor variables. To investigate the role of blood type in LARs and SARs after both vaccination doses, a sub-analysis was implemented in HCWs in whom blood type was recorded. Statistical analysis was performed with the SAS software (V9.4, SAS Institute Inc). Statistical significance level was set at p-value <0.05.

3. Results

A total of 502 HCWs who had 2 doses of the BNT162b2 vaccine according to the recommended schedule (21 days apart) were included in the study. The mean age (±SD) of the participants was 48.2 years (±12.97) (range: 22–70 years), and the majority of them (n = 275; 54.8%) were in the age groups of 40–59 years. The mean BMI (±SD) of the participants was 24.86 kg/m² (±4.58). Among the 502 HCWs, 393 (78.3%) were females, 230 (45.8%) were overweight, 139 (27.7%) were smokers and 240 (47.8%) had a medical history of underlying diseases (Table 1).

Table 1. Distribution of the demographic characteristics of 502 healthcare workers participating in the study

Variable	Frequency n (%)
Gender
Female	393 (78.3)
Male	109 (21.7)
Age group (years)
<30	47 (9.4)
30–39	91 (18.1)
40–49	117 (23.3)
50–59	158 (31.5)
≥60	89 (17.7)
BMI (kg/m^2)
<25	272 (54.2)
25–29.9	163 (32.5)
≥30	67 (13.3)
Smoking
No	363 (72.3)
Yes	139 (27.7)
Underlying diseases
No	262 (52.2)
Yes	240 (47.8)
Blood type
O	167 (33.3)
A	148 (29.5)
B	43 (8.6)
AB	17 (3.4)
NA	127 (25.2)

Abbreviations: BMI: body mass index; NA: not available.

After the first dose, 404 (80.5%) HCWs reported at least one LAR and 366 (72.9%) after the second dose (p value 0.004). After the first dose, 121 (24.1%) HCWs reported at least one SAR and 275 (54.8%) after the second dose (p value <0.0001).

After the first vaccine dose, at least one LAR was reported among 224/255 (87.8%) HCWs <50 years and among 180/247 (72.9%) HCWs >50 years (76.5 vs 70%, respectively, p-value< .0001). In contrast, after the second vaccine dose, there was not statistically significant difference in the reported LARs between the two groups (76.5 vs 70%, respectively, p-value: 0.1).

Most LARs and SARs were described by study participants as of mild or moderate severity, without preventing daily activities and are presented in Supplementary Table 1. Reactions were most frequently reported on the day following vaccination and resolved after a mean duration of 3 days. The most common local self-limited reactions after the first and second vaccine dose were injection site pain (79.5% and 71.1%) and edema (12.8% and 15.5%). There was an increasing proportion of SARs following the second vaccine dose. The most frequently detected SARs after the first and second vaccine dose included fatigue (13.4% and 39.0%), myalgias and arthralgias (9.0% and 27.9%), headache (13.6% and 30.3%) and fever (1.4% and 17.1%), respectively. In the current study, no severe hypersensitivity reactions, including anaphylaxis, had been observed among the vaccine recipients.

The possible associations of gender, age (expressed in decades), BMI, underlying diseases and smoking in the manifestation of LARs and SARs after the first and second dose of BNT162b2 vaccine are presented in Tables 2 and 3.

Table 2. Logistic derived odds ratio (OR) together with 95% confidence interval (95% CI) for local adverse reactions (LARs) following the first and second dose of the BNT162b2 vaccine by the study variables. Cumulative score includes local injection site pain and edema

Variable	Vaccine dose	Local injection pain	Local injection edema	Cumulative score of LARs
Gender (female vs male)	1st	1.53	1.02	1.32
		0.91–2.56	0.53–1.94	0.84–2.09
	2nd	1.56	1.07	1.39
		0.98–2.48	0.59–1.95	0.91–2.13
Age group (10 years more)	1st	0.73	0.97	0.82
		0.60–0.89	0,77–1.22	0.69–0.96
	2nd	0.92	0.9	0.91
		0.78–1.09	0.73–1.11	0.78–1.05
BMI (1 category more)	1st	0.68	1.15	0.82
		0.50–0.93	0.79–1.68	0.62–1.07
	2nd	0.98	1.23	1.08
		0.74–1.31	0.87–1.74	0.84–1.39
Underlying disease (Yes vs No)	1st	1.05	0.81	0.95
		0.66–1.67	0.47–1.41	0.64–1.40
	2nd	1.23	0.82	1.06
		0.82–1.84	0.5–1.37	0.74–1.53
Smoking (Yes vs No)	1st	0.88	1.57	1.15
		0.54–1.44	0.9–2.74	0.76–1.75
	2nd	0.57	1.22	0.72
		0.37–0.87	0.72–2.08	0.49–1.07

Abbreviations: BMI: body mass index;

Statistically significant (p-value < 0.05) results are marked in bold.

Table 3. Logistic derived odds ratio (OR) together with 95% confidence interval (95% CI) for systemic adverse reactions (SARs) following the first and second dose of the BNT162b2 vaccine by the study variables. Cumulative score includes fatigue, headache, myalgias-arthralgias, fever, gastrointestinal symptoms, lymphadenopathy and chills

Variable	Vaccine dose	Fatigue	Headache	Myalgias-Arthralgias	Fever	GI symptoms	LA	Chills	Cumulative score of SARs
Gender (female vs male)	1st	2.61	2.57	2.37	0.72	0.75	0.83	-	2.57
		1.14–5.95	1.13–5.86	0.90–6.25	0.05–9.69	0.07–7.83	0.06–12.15	-	1.39–4.73
	2nd	2.06	2.73	3.08	1.78	1.87	1.87	3.59	2.71
		1.26–3.35	1.53–4.86	1.73–5.49	0.83–3.84	0.51–6.90	0.51–6.90	1.06–12.24	1.76–4.19
Age group (10 years more)	1st	0.90	0.87	0.89	0.47	0.81	0.31	-	0.85
		0.72–1.12	0.69–1.09	0.68–1.16	0.15–1.48	0.35–1.87	0.08–1.25	-	0.71–1.01
	2nd	0.74	0.78	0.70	0.65	0.62	0.58	0.57	0.66
		0.63–0.87	0.66–0.93	0.59–0.83	0.51–0.82	0.38–1.00	0.38–0.89	0.42–0.76	0.57–0.76
BMI (1 category more)	1st	0.83	0.89	1.06	0.80	0.45	0.92	-	0.95
		0.55–1.24	0.61–1.31	0.68–1.66	0.09–6.80	0.06–3.56	0.11–7.96	-	0.70–1.29
	2nd	0.84	1.05	0.97	0.69	0.74	1.42	0.90	0.97
		0.64–1.11	0.78–1.41	0.73–1.30	0.44–1.07	0.29–1.88	0.71–2.85	0.53–1.52	0.76–1.23
Underlying disease (Yes vs No)	1st	0.92	1.55	1.05	-	0.48	-	-	1.08
		0.54–1.58	0.91–2.67	0.56–2.00	-	0.05–4.90	-	-	0.70–1.65
	2nd	0.97	0.88	1.09	1.41	1.81	0.83	2.13	1.05
		0.66–1.43	0.58–1.34	0.72–1.64	0.81–2.48	0.57–5.75	0.30–2.31	1.04–4.37	0.75–1.48
Smoking (Yes vs No)	1st	0.87	1.01	1.49	1.81	0.96	2.06	-	1.12
		0.48–1.57	0.56–1.79	0.78–2.85	0.15–21.29	0.10–9.47	0.17–25.22	-	0.71–1.77
	2nd	0.72	0.83	1.14	1.03	0.87	0.57	1.37	0.81
		0.47–1.09	0.53–1.32	0.74–1.77	0.56–1.90	0.23–3.25	0.16–2.04	0.65–2.89	0.56–1.17

Abbreviations: BMI: body mass index; GI: gastrointestinal; LA: lymphadenopathy

Statistically significant (p-value < 0.05) results are marked in bold.

In the logistic regression analysis, there was no association of gender or medical history of underlying diseases with LARs (Table 2). There was a negative association of age with local injection pain (OR: 0.73, 95% CI: 0.60–0.89, p-value: 0.002) and cumulative score (CS) of LARs (OR: 0.82, 95% CI: 0.69–0.96, p-value: 0.01) after the first dose. BMI was negatively associated with local injection pain after the first dose (OR: 0.68, 95% CI: 0.50–0.39, p-value: 0.02). Smoking status was negatively associated with local injection pain after the second dose (OR: 0.57, 95% CI: 0.37–0.87, p-value: 0.01).

Regarding SARs, BMI and smoking status were not associated with any ARs (Table 3). Female gender had a positive association with fatigue, headache and CS of SARs (OR: 2.57, 95% CI: 1.39–4.73, p-value: 0.003) following the first dose, as well as with fatigue, headache, myalgias and arthralgias, chills and CS of SARs (OR: 2.71, 95% CI: 1.76–4.19, p-value<0.0001) after the second dose. Age was negatively associated with fatigue, headache, myalgias and arthralgias, fever, lymphadenopathy, chills and a CS of SARs (OR: 0.66, 95% CI: 0.57–0.76, p-value<0.0001) after the second dose. There was also a positive association between underlying medical conditions and chills (OR: 2.13, 95% CI: 1.04–4.37, p-value: 0.04) after the second dose.

Concerning the possible association of blood type with ARs from the sub-analysis of 375 HCWs, a negative association between blood type B and local injection pain after the first dose (OR: 0.33, 95% CI: 0.15–0.73, p-value: 0.01) and a positive association of blood type O and fever after the second vaccination dose (OR: 2.97, 95% CI: 1.37–6.45, p-value: 0.01) comparing with the blood type A were found.

During the study period, some unusual ARs were recorded among the participated HCWs. More specifically, a 45-year-old male with a history of type 1 diabetes mellitus 20 days after the second dose presented with unilateral facial paralysis with drooping at the left corner of the mouth, dysarthria, inability to close the eye and decreased tearing, compatible with Bell’s palsy. The participant required a 3-week systemic use of corticosteroids for partial improvement of symptoms. Until now, the participant has not fully recovered.

Among the 502 HCWs, there were two who presented with supraclavicular lymphadenopathy following both vaccine doses: a 30-year-old female and a 31-year-old male. Even though the female reported unilateral supraclavicular lymphadenopathy that resolved within 3 days after vaccination, the male reported a bilateral location of the same AR approximately 3 hours after both vaccine doses that lasted for 1 week, resolving without any medication.

Furthermore, a 60-year-old female experienced serious tinnitus with temporary hearing loss 5 days after the first dose that lasted for over a month. The intense of symptoms was increased after the second dose and eventually responded to systemic use of corticosteroids.

Another notable case was a 65-year-old female with free prior medical history presenting with pleuritic and retrosternal pain. The onset of pain was 3 hours following the second dose and lasted for over 2 months. There was a negative electrocardiographic, ultrasonography and radiological control with subsequent resolution after systemic use of corticosteroids.

4. Discussion

In this study, the prevalence and severity of LARs and SARs after both doses of the BNT162b2 COVID-19 vaccine as well as their association with clinical and epidemiological characteristics of vaccinated HCWs were included. The administration of the BNT162b2 vaccine had a good safety profile in our cohort with most vaccine recipients developing self-limited LARs and SARs most frequently after the second vaccine dose.

LARs did not indicate significant differences after the first and second doses (79.5% vs 71.1%), however, the frequency and severity of SARs were higher after the second dose. This enhancement of SARs may possibly be attributed to the robust increase of total and neutralizing antibody titers after the administration of the second dose, which results in immune system induction.^9,10 Findings of the present study agree with a large-scale study from USA, which included 1.6 million participants, and injection site pain after both BNT162b2 vaccine doses did not present any significant differences (72.9% vs 79.3%).¹¹ However, common SARs, including fatigue and headache, were reported in 21.9% and 17.5% after the first dose as well as in 53.5% and 43.4% after the second dose, respectively, in line with our findings.¹¹

In our study, there is a gender-dependent association with SARs, especially with fatigue and headache after both vaccine doses, since females were 2–2.5 times more likely to develop these symptoms post-vaccination. In contrast to males, females had an increased risk of developing myalgias, arthralgias and chills after the second dose. The role of gender in the severity of ARs in both vaccine doses was also indicated in studies from South Korea in HCWs, which both show an increased proportion of ARs in females in contrast to males.^7,12

In the present study, a parameter that significantly affected the manifestation of SARs was age. An increase of age by one decade had a protective role in the development of almost all the most commonly reported ARs after the second dose. This negative association of age with the CS of LARs after the first dose and with the CS of SARs after the second dose may possibly be attributed to the impaired induction of total and neutralizing antibody titers of older compared to younger vaccine recipients, as demonstrated by other recent studies.^9,10 A large-scale study from the UK showed lower proportions in the development of SARs compared to our cohort.¹³ Since the median age of the participants was approximately 60 years and our study population was significantly younger (48.17 years) compared to the study population of Menni et al.,¹³ we assume that the differences of frequency and severity of SARs between the two studies are age-related, which we showed is negatively associated with the manifestation of ARs.

The vaccine recipients with underlying medical conditions had increased risk of developing chills after the second dose. Chills are considered one of the most common SARs following BNT162b2 vaccination.⁵ In a large study from Czech Republic in HCWs about vaccine side effects, a statistically significant increased prevalence of chills in participants receiving nonsteroidal anti-inflammatory drugs (NSAIDs) and antihistamine drugs was shown.⁸ However, in our study group, the presence of any underlying medical conditions with the manifestation of ARs was examined. More future studies are needed in order to enlighten the potential effect of common and uncommon comorbidities with vaccine, LARs and SARs.

To the best of our knowledge, this is the first study indicating ABO blood types as a predisposing or protective role against the development of post-vaccination ARs, such as local injection pain and fever, confirmed in the regression sub-analysis of the study parameters. The role of blood type in LARs and SARs remains also elusive. In our cohort, the negative association of blood type B with local injection pain after the first dose and the positive association of blood type O with fever after the second vaccination dose, respectively, do not clarify the determinant role of a certain blood type in the development of any ARs. There are studies that support the role of ABO blood types in COVID-19, but none of them is referred to vaccine reactogenicity and ARs manifestation.^14,15 Association analysis between ABO blood group and SARS-CoV-2 infection have shown that type A is associated with a higher risk of respiratory failure from COVID-19¹⁴ and type O with a lower risk of severe disease.¹⁵ However, further studies to confirm a pathophysiologic basis for these findings are required.

Bell’s palsy consists a rare medical condition associated with the Pfizer-BioNTech COVID-19 vaccine in four vaccine recipients during the phase III clinical trial.¹⁶ The incidence of Bell’s palsy did not exceed the incidence in the general population, and data are insufficient to determine a definite association between vaccination and Bell’s palsy.¹⁶ The onset of Bell’s palsy during clinical trials was variable, ranging from 37th day after the first dose to the 3rd, 9th, and 48th day after second dose, respectively.¹⁶ Recently, Shemer et al. reported 9 cases of BNT162b2 vaccine recipients in Israel with peripheral facial nerve palsy.¹⁷ Interestingly, eight out of nine of the patients were 51 years or older and six of them had a history of underlying cardiovascular disease.¹⁷ In our study, the vaccinated HCW who presented with Bell’s palsy was a 45-year-old male, younger than the patients who were reported by Shemer et al,¹⁷ but he had type 1 diabetes mellitus, a disease that often affects the cardiovascular system. Nevertheless, since data regarding the incidence of Bell’s palsy after immunization are limited, post-vaccine monitoring and future studies should enlighten possible predisposing factors of this rare complication.

An unsolicited SAR possibly attributed to vaccine was lymphadenopathy. Previous clinical trials have shown an estimated 0.3% prevalence of reported ipsilateral axillary and supraclavicular lymphadenopathy in BNT162b2 vaccine recipients.¹⁸ In our study, both axillary and supraclavicular lymphadenopathy were more frequently reported after the second vaccine administration and were usually unilateral with mild to moderate intense. The median onset of lymphadenopathy was approximately 3 days post-vaccination and lasted for a maximum of 10 days. Since the beginning of BNT162b2 vaccination worldwide, there are several reports of clinical cases across all age spectra with single supraclavicular lymphadenopathy.^19,20 To the best of our knowledge, this is one of the few reported cases of supraclavicular lymphadenopathy with bilateral location, probably as a result from a robust vaccine-induced immune response.³

Sudden tinnitus with or without temporary hearing loss consist of rare but notable medical conditions that affect daily activities and often require medication for symptoms relief. According to a UK database that records ARs following vaccination, among 33207 COVID-19 BNT162b2 mRNA-vaccine recipients between January and February 2021, a total of 196 tinnitus and 11 sudden hearing loss cases were reported.²¹ Recently, Parrino et al. described three cases of tinnitus following BNT162b2 vaccination;²² there was a 60-year-old male, with a known history of sensorineural hearing loss, presenting with tinnitus and impaired hearing after the first dose in whom systemic treatment with corticosteroids was proposed.²² This case is highly consistent with the case described in our study. Since a definite association of tinnitus or hearing loss with BNT162b2 has not been established yet and given the implications of a possible autoimmune underlying mechanism for these conditions,²² we believe that our report alongside other studies will improve the already existing surveillance in ARs from COVID-19 BNT162b2 vaccination and enlighten their pathogenesis and ARs.

Myocarditis and pericarditis, mainly in male adolescents and young adults, have recently been reported as rare and mild ARs following COVID-19 BNTb162b2 vaccination.^23,24 However, in a recent report of the Vaccine Adverse Event Reporting System (VAERS), between January and June 2021, there were 1226 reports of myocarditis, 507 of which were among vaccinees aged ≥30 years.²³ The vaccine recipient with retrosternal pain in our study did not meet any laboratory or radiological criteria for myocarditis (ST elevations on electrocardiogram, elevated troponin levels, cardiac magnetic resonance imaging findings etc). Given the highly variable clinical presentation of myocarditis in adults,²⁵ the cardiotropic nature of SARS-CoV-2 and the improvement of symptoms with corticosteroids,²⁴ a possible myocarditis diagnosis in the vaccine in our study following the second dose could not be excluded. Consequently, we suggest that the possibility of myocarditis should not only be considered in adolescents and young adults, but to all vaccine recipients of any age developing new chest pain after receiving COVID-19 BNT162b2 vaccine.

Limitation of the present study includes the limited number of participants, which does not allow the detection of very rare ARs. However, strengths of the study include the prospective design with very detailed epidemiological and medical history of the vaccine recipients. Present study also includes, for first time, association of AEs with ABO blood types and inflammatory habits, such as smoking.

5. Conclusion

The most common ARs of the BNT162b2 COVID-19 vaccine among healthcare workers were local self-limited reactions. In our cohort, the increased prevalence of LARs and SARs in females and younger age groups was consistent with the data reported from other studies. Rare but severe ARs after immunization should be further investigated in large-scale studies including participants from different ethnic and racial backgrounds. Further elucidation of the underlying pathophysiological mechanisms and potential predisposing factors to serious ARs will support mass immunization programs and improve social confidence to COVID-19 immunization.

Author contributions

FF, EBT and CD performed the collection of data. ND performed the statistical analysis. AM and VS designed and overviewed the study. FF, EBT and AM wrote the initial manuscript. All authors reviewed and approved the final manuscript.

Availability of data and material

Not applicable.

Code availability

Not applicable.

Consent to participate

Written informed consent was obtained from the participants.

Ethics approval

The study protocol was approved by the scientific and bioethics committee of “Aghia Sophia” Children’s Hospital (No: 2794) and was performed in accordance with the ethical standards as laid down in the 1964 Declaration of Helsinki.

Disclosure statement

All authors declare no competing interests regarding the present study.

Supplementry material

Supplemental data for this article can be accessed on the publisher’s website at https://doi.org/10.1080/21645515.2021.1985356

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.