ORIGINAL ARTICLE

https://doi.org/10.5005/jp-journals-10081-1405
Pediatric Infectious Disease
Volume 5 | Issue 4 | Year 2023

Demographic and Diagnostic Predictors of Respiratory Syncytial Virus in Children of Less than 2 Years Presenting with Acute Respiratory Tract Infection

Nikhil Raj¹ https://orcid.org/0000-0001-8245-7722, Priyanka Gupta², Dipti Agarwal³, Jyotsna Agarwal⁴ https://orcid.org/0000-0003-0568-7959, Jaya Garg⁵ https://orcid.org/0000-0003-4677-8339

^1,4,5Department of Microbiology, Dr Ram Manohar Lohia Institute of Medical Sciences, Lucknow, Uttar Pradesh, India

²Department of Microbiology, Kalyan Singh Super Specialty Cancer Institute, Lucknow, Uttar Pradesh, India

³Department of Pediatrics, Dr Ram Manohar Lohia Institute of Medical Sciences, Lucknow, Uttar Pradesh, India

Corresponding Author: Jaya Garg, Department of Microbiology, Dr Ram Manohar Lohia Institute of Medical Sciences, Lucknow, Uttar Pradesh, India, Phone: +91 93364 23308, e-mail: jaya_bhu@rediffmail.com

Received on: 03 March 2023; Accepted on: 06 April 2023; Published on: 14 December 2023

ABSTRACT

Background: Worldwide respiratory syncytial virus (RSV) is one of the leading infectious causes of acute respiratory tract infection (ARTI) and related death in children under the age of 2 and it accounts for 60–80% of bronchiolitis presentations in developing countries like India. The present study was done to determine the diagnostic and demographic predictors of RSV in children <2 years old who presented with ARTI.

Materials and methods: This was a pilot study that was performed over a period of 18 months in a tertiary healthcare facility in Northern India. A total of 55 nasopharyngeal swab samples from cases with ARTI presentation were collected in viral transport media (VTM) and were tested for RSV using reverse transcription polymerase chain reaction (RT-PCR).

Result: A total of 55 clinically suspected cases of ARTI with age <2 years, eight (14.5%) cases were positive for RSV RT-PCR, male gender, ear discharge, risk factors such as premature birth, bottle feeding, and chest X-ray findings such as hyperinflation had a significant association with children with RSV (p < 0.05) which can be used as diagnostic predictors for RSV during the study period peak of RSV cases occurred in between November and December (winter season).

Conclusion: Diagnostic predictors are very important in identifying RSV in resource-limited countries like India where an expensive, technically cumbersome, and complex molecular confirmatory test is not possible. This study identifies a set of risk factors, demographic characteristics, and radiological findings that will guide clinicians to start management for RSV.

How to cite this article: Raj N, Gupta P, Agarwal D, et al. Demographic and Diagnostic Predictors of Respiratory Syncytial Virus in Children of Less than 2 Years Presenting with Acute Respiratory Tract Infection. Pediatr Inf Dis 2023;5(4):109–113.

Source of support: Nil

Conflict of interest: None

Keywords: Acute lower respiratory infection, Children, Respiratory syncytial virus, Reverse transcription polymerase chain reaction

BACKGROUND

According to the World Health Organization (WHO) estimates, acute respiratory tract infections account for around 2 million deaths in the pediatric population each year across the world, a wide majority of which occur in low- and middle-income countries.¹ In India, according to the fourth National Family Health Survey data about 400,000 children die each year due to acute respiratory tract infection.² Worldwide respiratory syncytial virus (RSV) is one of the leading infectious causes of acute respiratory tract infection (ARTI) and death in children under the age of 2, accounting for 60–80% of bronchiolitis presentations, associated with significant mortality and high rates of hospitalization of in pediatric population.³ The rates of RSV detection in various studies conducted across India targeting children of <2 years of age in the last 15 years (2008–2023) have shown a varying prevalence ranging from 2.1 to 62.4% which is higher compared to children from other age-groups.⁴ According to the Centers for Disease Control’s National Foundation for Infectious Disease progress report, RSV accounts for approximately 58,000–80,000 hospitalizations and 2.1 million outpatient/nonhospitalization visits among young children in the United States.⁵

Clinically diagnosing RSV infection is often challenging as it is associated with general symptoms like pharyngitis, ear discharge, fever, cough, and shortness of breath, which are not specific and indistinguishable from other bacterial and viral respiratory infections. However, according to the American Association of Pediatrics (AAP) guidelines clinical judgment should be used as a feasible way to diagnose RSV infections as the use of virological diagnostic tests rarely improves the outcome of these infections.⁶ Enzyme immunoassays/rapid diagnostic tests (RDTs) are the most common diagnostic tests which are used due to their low-cost and turnaround time of 30 minutes, though these tests are highly specific having a specificity of >95% they have 50–90% sensitivity compared to polymerase chain reaction (PCR).⁷ Therefore, a negative RDT test result should not rule out RSV disease if appropriate clinical symptoms are present. Confirmation of RSV is done by reverse transcription-PCR (RT-PCR) which is the gold standard but highly expensive making its use impractical in low- and middle-income countries therefore diagnosis of RSV infection is often delayed and missed, which affects clinical management and outcomes.

There are limited studies from India that have analyzed recent prevalence, demography, and clinical predictors of RSV infections in children <2 years old. The present study was done to determine the prevalence of RSV in children <2 years presented with acute respiratory tract infection (ARTI). The study identifies a set of risk factors that may predict the development of RSV-associated ARTI in children under 2 years of age, This will help as an evidence-based resource for early diagnosis and evaluation of RSV disease.

Materials and Methods

This prospective observational pilot study was performed over a period of 18 months (December 2019 and June 2021) at Dr Ram Manohar Lohia Institute of Medical Sciences, Lucknow. Both outpatient and hospitalized cases of age >2 years were included which met WHO case definition of ARTI, that is, the presence of cough, coryza, sore throat, fever with breathlessness of >7 days duration, and increased respiratory rate with or without wheeze.

Adequate demographic and clinical details like age, sex, presenting symptoms, signs, birth-related risk factors, preexisting illness, neonatal intensive care unit (NICU) stay, auscultatory findings, and radiological assessment (as evaluated by a physician) were documented. Questionnaires for risk factors assessment like host-related factors, personal history, and family history were filled out accordingly.

Clinically suspected cases of ARTI were further confirmed via RT-PCR for RSV disease. A total of 55 nasopharyngeal swab samples from cases of ARTI were collected in viral transport media (VTM) after written informed consent from the guardians of patients. RNA was extracted and using a REVERTA-L RT kit (Central Research Institute for Epidemiology, Moscow, Russia), complementary DNA was obtained which was tested in parallel on a PCR plate for RSV along with positive and negative template controls and internal control using PCR assay kit for RSV (QIAGEN, Venlo, Netherlands). Samples with a cycle threshold value of <40 were considered positive, test standardization was done using known PCR-positive RSV control and PCR-negative RSV control to validate the test procedure prior to testing clinical samples of the study.

Statistical Analysis

It was performed using Statistical Package for the Social Sciences version 26. Clinical, radiological, and demographic characteristics of RSV RT-PCR positive confirmed cases were compared with RSV RT-PCR negative cases. The p-values were calculated using the Chi-squared test, a p-value of <0.05 was considered statistically significant. Ethical clearance was duly obtained from the Institute Ethics Committee (IEC) (IEC No. 39/19) before starting the study.

RESULTS

In this study, the demographic, clinical, and seasonal factors were compared between RSV-positive and RSV-negative cases to find predictors of RSV infection out of a total of 55 clinically suspected cases of ARTI with age <2 years, eight (14.5%) of cases were positive for RSV RT-PCR (Fig. 1).

Fig. 1: Month-wise distribution of RT-PCR confirmed RSV positive vs ARTI cases

On analyzing the demographic profile of RSV-positive patients we observed that the majority of RSV (62.5%) positive cases were male and male gender had a statistically significant association with RSV-positive cases (p-value of 0.016), however, there was no statistically significant difference between the RSV-positive and RSV-negative groups with regard to age, presence of older sibling, and socioeconomic status as shown in Table 1.

**Table 1:** Represents demographic evaluation of RSV RT-PCR positive ARTI cases and RSV RT-PCR negative ARTI cases
S. No.	Age	ARTI cases (n = 55)		p-value	Chi-square score
S. No.	Age	RSV RT-PCR positive n = 8 (%)	RSV RT-PCR negative n = 47 (%)	p-value	Chi-square score
1	<6 m	5 (62.5%)	23 (49%)	0.478	0.503
2	7–12 m	1 (12.5%)	7 (14.8%)	0.858	0.0315
3	13–18 m	1 (12.5%)	8 (17%)	0.749	0.102
4	19–24 m	1 (12.5%)	9 (19.2%)	0.652	0.203
	Gender
5	Male	5 (62.5%)	10 (21.3%)	0.016	5.857
6	Female	3 (37.5%)	37 (78.7%)	0.016	5.857
	Demographic risk factor
7	Presence of older siblings	4 (50%)	23 (48.9%)	0.956	0.003
8	Lower socioeconomic status	5 (62.5%)	37 (78.7%)	0.318	0.997
9	Rural residence	4 (50%)	16 (34%)	0.386	0.752

ARTI, acute respiratory tract infection; RSV, respiratory syncytial virus; RT-PCR, reverse transcription polymerase chain reaction

The major clinical symptom that had a statistically significant association with RSV-positive cases was ear discharge (25% p < 0.001), while nasal congestion (37.5% p-value 0.009) had a significant association with RSV-negative cases and other clinical symptoms that were evaluated but didn’t have any significant association with RSV-positive cases are shown in Table 2. On evaluating clinical signs in the cases we observed no statistically significant difference between the RSV-positive and negative groups in terms of tachypnea, dehydration, cyanosis, rash, chills, sternal/intercostal retractions, and pleurisy as shown in Table 2.

**Table 2:** Showing clinical evaluation of RSV RT-PCR positive ARTI cases and RSV RT-PCR negative ARTI cases
S. No.	Clinical characteristics	ARTI cases (n = 55)		p-value	Chi-square score
S. No.	Clinical characteristics	RSV RT-PCR positive n = 8 (%)	RSV RT-PCR negative n = 47 (%)	p-value	Chi-square score
A	Symptoms
1	Cough	8 (100%)	42 (89.4%)	0.333	0.936
2	Nasal congestion	3 (37.5%)	38 (80.9%)	0.009	6.771
3	Shortness of breath	7 (87.5%)	37 (78.7%)	0.566	0.329
4	Fever	7 (87.5%)	38 (80.9%)	0.652	0.203
5	Coryza	6 (75%)	38 (80.9%)	0.702	0.146
6	Ear discharge/otitis media	2 (25%)	0 (0%)	<0.001	12.193
7	Diarrhea	1 (12.5%)	2 (4.3%)	0.342	0.901
8	Difficulty in feeding	4 (50%)	32 (68.1%)	0.320	0.989
B	Signs
1	Tachypnea	5 (62.5%)	30 (63.8%)	0.943	0.005
2	Dehydration	1 (12.5%)	3 (6.4%)	0.538	0.379
3	Cyanosis	1 (12.5%)	4 (8.5%)	0.717	0.132
4	Rash	1 (12.5%)	2 (4.3%)	0.342	0.901
5	Chills	1 (12.5%)	2 (4.3%)	0.342	0.901
6	Sternal/intercostal retractions	3 (37.5%)	11 (23.4%)	0.398	0.716
7	Pleurisy	0 (0%)	1 (2.1%)	0.677	0.173

ARTI, acute respiratory tract infection; RSV, respiratory syncytial virus; RT-PCR, reverse transcription polymerase chain reaction; Bold values indicate significant association

None of the auscultatory findings like decreased breath sounds, pleural friction rub, rales, and prolonged expiratory phase had a statistically significant association with RSV positive. On evaluating chest X-ray we observed that findings like hyperinflation of lungs (75% p-value of 0.009), pneumonitic patches (87.5% p-value of <0.001), lobar consolidation (75% p-value < 0.001), and pleural effusion (25% p-value < 0.001) had a significant association with RSV positive cases as shown in Table 3.

**Table 3:** Showing auscultatory and radiological evaluation of RSV RT-PCR positive ARTI cases and RSV RT-PCR negative ARTI cases
S. No.	Clinical characteristics	ARTI cases (n = 55)		p-value	Chi-square score
S. No.	Clinical characteristics	RSV RT-PCR positive n = 8 (%)	RSV RT-PCR negative n = 47 (%)	p-value	Chi-square score
A	Auscultatory findings
1	Decreased breath sounds	2 (25%)	15 (31.9%)	0.696	0.153
2	Pleural friction rub	0 (0%)	2 (4.3%)	0.552	0.353
3	Rales/crackles on auscultation	4 (50%)	25 (53.2%)	0.867	0.028
4	Prolonged expiratory phase	0 (0%)	9 (19.1%)	0.176	1.832
B	Radiological features
1	Hyperinflation of lung	6 (75%)	13 (27.7%)	0.009	6.776
2	Nodes	0 (0%)	1 (2.1%)	0.677	0.173
3	Pneumonitic patches	7 (87.5%)	6 (12.8%)	<0.001	21.154
4	Lobar consolidation	6 (75%)	5 (10.6%)	<0.001	17.699
5	Pleural effusion	2 (25%)	0 (0%)	<0.001	12.193

ARTI, acute respiratory tract infection; RSV, respiratory syncytial virus; RT-PCR, reverse transcription polymerase chain reaction; Bold values indicate significant association

In this study, we also analyzed various risk factors and their association with RSV as shown in Table 4. The risk factors that had a significant association with RSV-positive cases were premature birth (62.5%, p-value of 0.005), bottle feeding (75% p-value < 0.001), and NICU stay (62.5% p-value of 0.005).

**Table 4:** Risk factors evaluation of RSV RT-PCR positive ARTI cases and RSV RT-PCR negative ARTI cases
S. No.	Risk factors	ARTI cases (n = 55)		p-value	Chi-square score
S. No.	Risk factors	RSV RT-PCR positive n = 8 (%)	RSV RT-PCR negative n = 47 (%)	p-value	Chi-square score
1	Congenital or acquired neurological disease	2 (25%)	7 (14.9%)	0.475	0.510
2	Congenital or acquired immune deficiency	1 (12.5%)	2 (4.3%)	0.342	0.901
3	Congenital heart disease	1 (12.5%)	2 (4.3%)	0.342	0.901
6	Airway anomaly	1 (12.5%)	1 (2.1%)	0.147	2.099
7	H/o bottle feeding	6 (75%)	5 (10.6%)	<0.001	17.699
9	NICU admission	5 (62.5%)	8 (17%)	0.005	7.834
10	Premature birth	5 (62.5%)	8 (17%)	0.005	7.834

ARTI, acute respiratory tract infection; RSV, respiratory syncytial virus; RT-PCR, reverse transcription polymerase chain reaction; H/o, history of; Bold values indicate significant association

Based on the observations of the current study, RSV was not prevalent throughout the year but showed peaks in certain months. Major RSV peaks were observed in the month of November where a maximum (62.5%) RSV cases were detected, minor peaks of two (25%) cases and only one (12.5%) case were observed in the month of December and October, respectively.

DISCUSSION

The RSV has been recognized as a major cause of acute respiratory tract infections, especially in children <2 years of age. In this study, we highlighted the clinical, radiological, and demographic predictors of RSV-associated ARTI which would help clinicians to come to an early diagnosis as shown in Figure 2.

Fig. 2: Showing predictors of RSV infection

The prevalence of RSV in our study was 14.5% which was in agreement with a study by Babu et al. in Chennai where they reported a prevalence of 14.5%, in contrast, a higher prevalence of 22 and 21.3% was reported by Gupta et al. and Singh et al. in their study, and a lower prevalence of 2.1% was reported by Panda et al. in their study.⁸^,¹¹ These differences in RSV prevalence were due to the different selection criteria of patients, their age-group, and the diagnostic test used, as studies using serological diagnostic methods may have a high rate of RSV detection, due to the low specificity of these tests, presence of maternal antibodies, and sustained level of antibodies in past infection.

Various studies have reported male gender as a risk factor for RSV disease as male infants have a comparatively smaller airway diameter than female infants making them more susceptible to RSV infection In this study we observed that the male gender had a significant association with RSV similar observations were reported by Pangesti et al. in their study.¹²

In this study cough, shortness of breath, fever, and coryza was found to be the predominant symptoms associated with both RSV-positive and negative cases however, these symptoms didn’t have a significant association with RSV positivity while ear discharge/otitis media which was seen in 25% cases had a significant association with RSV-positive cases as it is believed that most ear discharge/otitis media episodes occur as complications of viral acute respiratory tract infection and various studies have reported that RSV is the most common virus associated with otitis media.¹³

In this study, we observed that general auscultatory finding was not very helpful in predicting RSV as none of these findings had a significant association with RSV cases however Szczawińska-Popłonyk et al. in their study reported that crackles and decreased breath sound on auscultation had a significant association with RSV cases.¹⁴ In our study, chest X-ray has proven to be a useful tool to predict RSV infection where RSV-positive cases presented as hyperinflation of lungs, pneumonitic patches, lobar consolidation, and pleural effusion; however, according to a study by Szczawińska-Popłonyk et al., chest X-ray examination was not useful in predicting RSV associated ARTI.¹⁴

In this study, we found that bottle-feeding and preterm delivery were significantly associated with RSV infection, which may be related to impaired pulmonary development and the absence of passive immunization by maternal antibodies that offer protection against these viruses., these findings were in agreement with those reported by Jang et al. and Welliver.¹⁵^,¹⁶

In this study peak of RSV cases occurred between November and December (winter season) which could be due to increased stabilization of the lipid envelope and viability of these enveloped viruses leading to more efficient transmission of the virus. Similar seasonality was also reported by Hindupur et al. in their study.¹⁷

Study Limitation

This was a pilot study with a small sample size of 55 cases, large-scale studies may be undertaken to confirm the findings of this study.

CONCLUSION

Diagnostic predictors are very important in identifying RSV in resource-limited countries like India where costly and technically cumbersome molecular confirmatory test is not possible. This study identifies the risk factors, demographic characteristics, and radiological findings which will guide clinicians to start management for RSV. The study also identifies the prevalence of RSV in children <2 years and alarms the higher authorities of India to include RSV vaccination in the national immunization schedule to combat the infection before it spreads in our country.

ACKNOWLEDGMENTS

The authors would like to thank healthcare workers of pediatric wards and technicians of the microbiology lab for their assistance in sample collection and processing.

Ethics Committee Approval

Ethical clearance was duly obtained from the Institute Ethics Committee (IEC No. 39/19) before starting the study.

Informed Consent

Written informed consent duly signed by guardians of children involved in this study was taken prior to sample collection.

ORCID

Nikhil Raj https://orcid.org/0000-0001-8245-7722

Jyotsna Agarwal https://orcid.org/0000-0003-0568-7959

Jaya Garg https://orcid.org/0000-0003-4677-8339

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