Introduction

Acute respiratory infections (ARIs) are the most common human diseases, with children being particularly vulnerable. The incidence of ARIs in the paediatric population is on average 2–3 times higher than in adults [1–2]. Respiratory syncytial virus (RSV) has been identified as the most common cause of acute viral respiratory infections in infants and children [1–5]. Worldwide, 33 million cases of RSV infection are recorded annually in children under 5 years of age, leading to 3.6 million hospitalisations and 118,200 deaths [6]. Among preterm infants, the RSV‑associated hospitalisation rate is significantly higher – 1.69 to 3.87 times than in full‑term infants [7]. Short‑lived post‑infection immunity and the existence of multiple viral genotypes determine a high probability of reinfection [8–10].

Notably, the majority of ARIs are mild or moderate and do not require hospitalisation. Due to insufficient laboratory verification of aetiology at the outpatient level, most cases of RSV infection in children and adults are not captured in official statistics. The predominance of non‑severe forms does not mean the absence of economic and societal consequences. Incomplete official statistics significantly affect the calculation of the economic burden of RSV infection, necessitating modelling. At the same time, data on more than 3 million hospitalisations and at least 100,000 deaths of children under 5 years of age annually worldwide from RSV infection and its complications allow considering this disease as socially significant and economically costly, both in the short and long term [11]. Even relatively mild cases in children during the first two years of life can lead to bacterial complications such as bronchitis, pneumonia, acute otitis media, and may contribute to the development of bronchial asthma, requiring additional treatment costs.

An assessment of the economic burden of RSV infection in our country was conducted relatively recently [12]. Using modelling, it was found that the average medical costs per case of RSV infection with lower respiratory tract involvement were RUB 7,315 for children under 1 year of age, RUB 5,369 for children aged 1 to 2 years, and RUB 4,530 for children aged 2–5 years. Higher costs in children under 1 year of age are due to a higher estimated hospitalisation rate, with average costs ranging from RUB 34,239 to RUB 46,219. Overall, the economic burden attributed to RSV infection was estimated by the authors at RUB 12.23 billion, of which medical costs accounted for RUB 2.27 billion (18.5%). That study was largely based on assumptions and scientific premises, including, as the authors themselves emphasise, data from foreign meta‑analyses. Without diminishing the importance of the aforementioned study, we believe that the key unresolved issues requiring clarification and development are: assessment of the burden of RSV infection in children aged 0–2 years, as the most vulnerable group, based on real clinical and epidemiological data, and refinement of indirect societal costs due to child mortality from RSV infection.

Long‑term, up‑to‑date anonymised monitoring data on RSV infection conducted by the Smorodintsev Research Institute of Influenza of the Ministry of Health of Russia allow calculating the socio‑economic burden of this disease in the population of children aged 0–2 years in Russia, which was the aim of this study.

Materials and Methods

The estimation of the number of RSV infection cases in children aged 0–2 years in 2022–2025 was based on an analysis of the anonymised database of laboratory‑confirmed monitoring data from the Smorodintsev Research Institute of Influenza. Information on influenza and ARVI cases was obtained by the Institute from 18 sentinel cities in the 2022–2023 season, 21 cities in 2023–2024, and 34 cities in 2024–2025. The highest proportion of RSV infection (12.3%) in the ARVI structure was recorded in the 2022–2023 season, and the lowest (5.8%) in 2024–2025.

For extrapolation to determine the number of cases in this age cohort across the entire country, a specific correction factor was introduced, calculated as follows:

CF = 1 / (population aged 0–2 years in the monitoring cities / population aged 0–2 years in the Russian Federation), where

CF – correction factor;population aged 0–2 years in the cities under monitoring by the Smorodintsev Research Institute of Influenza – 1,491,711 persons;population aged 0–2 years in the Russian Federation in 2024 – 3,955,095 persons¹.

The correction factor thus calculated is 2.65. Its application is as follows: based on the monitoring data of the Smorodintsev Research Institute of Influenza in the 2024–2025 season, in 34 cities of the country, 1,597,882 cases of ARVI were recorded in children aged 0–2 years. Following the logic of minimum‑maximum RSV incidence in this patient group, and taking into account the above data, it is possible to calculate the number of cases at the national level. To do this, the number of cases in the monitoring cities is multiplied by the correction factor (a scientific assumption based on real laboratory‑confirmed data). The minimum number of cases calculated in this way was: 1,597,882 ARVI cases × 5.8% RSV cases × 2.65 = 245,723 RSV cases in the country. The maximum calculated similarly was: 1,597,882 × 12.3% × 2.65 = 521,101 RSV cases (Table 1). Also, according to aggregated data from the Smorodintsev Research Institute of Influenza, 83.8% of children received outpatient medical care, while the remaining 16.2% were hospitalised, some of whom were admitted to the intensive care unit.

Table 1. Incidence of RSV infection

ParameterMinimumMaximumSourceNumber of children aged 0–2 years in the Russian Federation3,955,0953,955,095RosstatNumber of children aged 0–2 years in monitoring cities1,491,7111,491,711Own data of the Smorodintsev Research Institute of InfluenzaNumber of ARVI cases in children aged 0–2 years in monitoring cities, 20241,597,8821,597,882Own data of the Smorodintsev Research Institute of InfluenzaRSV infection in children aged 0–2 years in the Russian Federation245,723521,101Calculated dataOf which hospitalised (rate 16.2%)39,80784,418Calculated dataOf which treated outpatient (rate 83.8%)205,916436,683Calculated data

We divided clinical cases of RSV infection into 4 groups (patient models) according to the nature of the disease course:

Outpatients were distributed between Models 1 and 2 in a 50:50 ratio (assumption). Hospitalised patients, based on the Smorodintsev Research Institute of Influenza data, were distributed between Models 3 and 4 in a ratio of 72.7% and 27.3%, respectively. For Models 1–2, the total minimum calculated number was 205,916 cases, and the maximum – 436,683. For Model 3 – minimum 28,940 cases, maximum 61,372. For Model 4 – 10,867 and 23,046 cases, respectively.

The cost‑of‑illness calculation was performed for one season; for the assessment of long‑term consequences of RSV infection, modelling was carried out over the entire expected life expectancy. Direct medical costs (emergency medical services, inpatient and outpatient treatment) and non‑medical costs (temporary disability benefits to parents caring for a sick child) were considered, as well as indirect costs (loss of gross domestic product (GDP) due to one parent's absence from work to care for a sick child).

The cost of drugs included in the list of vital and essential medicines (VED) was calculated based on the registered maximum ex‑factory price² including VAT and wholesale mark‑ups; for drugs not included in the VED list, data from the PharmIndex portal were used.

Outpatient medical care costs were determined by the duration of the disease and the necessary number of clinic visits, and are presented according to the tariffs of the Compulsory Health Insurance Fund (CHI) for St. Petersburg [13]. The cost of an emergency medical service call was set at RUB 6,119.90. Inpatient medical care costs in Models 3 and 4 were determined considering disease severity and the need for ICU stay. Inpatient costs were also assessed according to St. Petersburg tariffs [13].

When assessing direct non‑medical costs (temporary disability payments to one parent caring for a sick child), it was taken into account that the average daily benefit in 2025 was RUB 3,205.86, and the proportion of parents who were employed was estimated at 80%.

Additionally, lost GDP (indirect costs or productivity losses) due to parental care for a child was calculated. GDP per capita in 2024 was RUB 2,571.71 per day.

When assessing long‑term consequences in case of death from RSV infection, we estimated not only the economic losses, which include lost GDP over the un‑lived years horizon, but also the value of those years themselves, i.e., actual and potential losses. They were calculated using the formula:

VLY = VSLY × (LE – A), where

VLY – value of lost years due to child death in a given year;VSLY – value of a statistical life‑year in a given year;LE – life expectancy;A – age at death (for ages 0–2 years, it was taken as an average of 1 year).

The value of an un‑lived life‑year was set at RUB 513,000 [14]. Life expectancy in Russia in 2025 was 73.4 years. According to Rosstat data for 2024, the probability of expected employment in the respective age groups averaged 32 years. Discounting of the value of lost life‑years and GDP in case of child death from RSV infection was performed at a rate of 3.5%.

For Models 1–2, care for RSV patients is provided by a district paediatrician; in case of certain bacterial complications, an otorhinolaryngologist (ENT) and a pulmonologist are involved.

Within Model 1, it was assumed that a child receives care at home once (cost RUB 1,039.6) and visits the clinic twice (RUB 955.3 × 2) during the illness period. For calculating medical care costs, current tariffs were used [13]. The duration of uncomplicated RSV infection is 10 days. In mild cases, therapy follows general principles – normalisation of body temperature, use of antitussives for severe cough, and decongestants to facilitate nasal breathing; total drug costs amount to RUB 2,735. Based on these data, total direct medical costs per child are RUB 5,686. Non‑medical costs (benefits for child care) amount to RUB 25,647, and GDP loss due to parental care – RUB 20,547.

For Model 2, we included two home visits by a paediatrician and three clinic visits, plus consultations with an ENT specialist and a pulmonologist (costs RUB 669.1 and RUB 661.0 respectively). Disease duration 15–18 days, drug therapy costs higher than in Model 1 due to additional medications for cough, rhinorrhoea, and considering the proportion of patients with prolonged illness due to complications (e.g., otitis). Total drug costs estimated at RUB 3,288, and total direct medical costs RUB 9,563 per patient. Parental benefit for sick leave is RUB 39,240, GDP loss – RUB 31,478.

Direct costs for Model 3 were determined based on prior outpatient treatment followed by hospitalisation with (25%) or without (75%) community‑acquired pneumonia (duration 14 or 7 days respectively (Table 2)). It is accounted that the patient is transported to the hospital by an emergency team. Thus, total direct medical costs per patient are estimated at RUB 131,661, non‑medical costs – RUB 61,681, indirect costs – RUB 49,480.

Table 2. Direct medical costs during hospitalisation for RSV infection [13]

Tariff code descriptionTariff, RUBBed‑daysModels 3 and 4: Influenza, ARVI80,093.007Models 3 and 4: Community‑acquired pneumonia (under 3 years)159,051.2014Model 4: Severe sepsis (SOFA <4) for ICU599,135.0015Model 4: Severe sepsis (SOFA ≥4) for ICU1,339,574.4030

For Model 4, all costs as for Model 3 (emergency medical care, inpatient treatment, and outpatient care for 10 days after discharge) were included, plus the costs of ICU stay (Table 2). When estimating ICU costs, we considered the probability that in 80% of cases care is provided under the tariff "Severe sepsis (SOFA <4) for ICU", and in the remainder – under "Severe sepsis (SOFA ≥4) for ICU". Non‑medical costs amounted to RUB 107,845, taking into account the proportion of patients with prolonged illness due to various complications (10%) as in Model 2, the proportion of patients developing pneumonia (25%) requiring longer hospitalisation (14 days) as in Model 3, and varying ICU stay duration (15 days in 80% and 30 days in 20%). Indirect costs were RUB 86,512.

Reliability of results across all models was assessed by sensitivity analysis on the main parameter – population size. Thus, the study was a cost modelling exercise based on the population size derived from baseline real clinical and epidemiological monitoring data from the Smorodintsev Research Institute of Influenza. The burden of RSV infection was calculated from the perspective of the state and society.

Results

Figures 1–3 and Table 3 present the obtained results.

When estimating costs per RSV patient over one season, the following values were obtained: total direct and indirect costs (including non‑medical) naturally increased from Model 1 to Model 4, amounting to RUB 51.9 thousand, RUB 80.3 thousand, RUB 242.8 thousand, and RUB 1.07 million, respectively.

Separately, indirect losses associated with fatal outcomes from RSV infection were considered, namely the value of un‑lived life‑years. It was assumed that such an outcome is applicable only in Models 3 and 4. For the entire target population, these losses for Models 3 and 4 were RUB 2.3 trillion and RUB 894.1 billion, respectively, over the lifetime.

Figure 1A. Total expenditures per RSV patient aged 0–2 years per season depending on disease severity

Figure 1B. Structure of total expenditures for one RSV patient by Model

Figure 2. Total expenditures for the target paediatric population during one season for the minimum estimated number of RSV cases (without long‑term consequences)

Table 3. Total costs for the target paediatric population

Cost categoryDefinitionModel 1 (102,958 RSV cases)Model 2 (102,958 RSV cases)Model 3 (28,940 RSV cases)Model 4 (10,867 RSV cases)Total for populationDirect medical costsEmergency medical services, RUB--177,109,90666,504,953243,614,859 Inpatient RSV treatment, RUB--3,468,626,8529,422,544,01612,891,170,868 Outpatient RSV treatment, RUB303,746,692646,082,04285,378,78832,059,8231,067,267,345 Outpatient drug therapy, RUB281,651,476338,495,66079,168,14329,727,720729,042,999Direct non‑medical costsChildcare benefit payments, RUB2,640,553,9534,040,047,5491,785,042,4791,171,954,1349,637,598,115Indirect costsLost GDP, RUB2,118,224,9453,240,884,1671,431,942,530940,129,4297,731,181,071Total for population per 1 season 5,344,177,0668,265,509,4177,027,268,69811,662,920,07532,299,875,256Long‑term consequencesValue of lost un‑lived years, RUB--2,381,226,209,644894,152,910,1663,275,379,119,810Total for population per 1 season + long‑term consequences (value of lost un‑lived years) 5,344,177,0668,265,509,4172,388,253,478,342905,815,830,2413,307,678,995,066

Notes: RSV – respiratory syncytial virus.

Figure 3A. Weighted average costs for RSV treatment per target population without the value of lost life‑years

Figure 3B. Total costs for the population by severity of RSV without the value of lost life‑years

Thus, for a patient population of 245,723, the total costs (including long‑term consequences) amounted to RUB 3.3 trillion. Direct medical costs accounted for RUB 14,931,096,071, or 46.2% of the treatment period costs without long‑term consequences. The largest share of direct medical costs was inpatient care – RUB 12,891,170,868. Relative to the total economic burden, direct medical costs constituted 0.45%. The vast majority of total costs were attributable to long‑term consequences – the value of lost (un‑lived) life‑years, which amounted to RUB 3,275,379,119,810, or 99% of the total economic burden. Similarly, the socio‑economic burden of RSV infection at the maximum estimated seasonal incidence (521,102 cases) amounted to RUB 7.014 trillion.

Figure 4 shows the results of the sensitivity analysis when varying the number of RSV cases.

Figure 4. Cost dynamics with changes in RSV case numbers (sensitivity analysis)

The sensitivity analysis results showed that when the key parameter (population size) deviated, the cost difference between the minimum and maximum incidence scenarios remained positive, confirming the robustness of the model.

Discussion

We have for the first time calculated the economic burden of RSV infection in children aged 0–2 years for the Russian Federation, based on a combination of real‑world surveillance data, expert opinion on four severity levels, and modelling. The results convincingly demonstrate the socio‑economic burden on society associated with RSV infection and the possible underestimation of its consequences for the state. It should be noted that both direct medical and non‑medical costs, as well as indirect costs, were accounted for over the horizon of one epidemic season, with the maximum possible stratification of patient groups by severity based on clinical expert assessment. Separately, the cost of lost life‑years in case of fatal outcome during severe RSV infection was estimated.

At the outpatient stage, costs per child may seem relatively low – RUB 51,906 per patient without complications and RUB 80,280 with complications (total). However, given the potential number of cases, they translate into significant public health expenditures. In moderate and severe cases, the largest share of direct medical costs is inpatient care.

Differences in burden estimates by different authors highlight the complexity of such calculations for acute seasonal diseases. Furthermore, estimates are influenced by case‑fatality rates and long‑term consequences of infection, including treatment of potentially triggered diseases such as bronchial asthma, for which RSV infection may act as a trigger.

Conclusion

Respiratory syncytial viral infection in children aged 0–2 years is characterised by a substantial socio‑economic burden for society and the state. The costs per case are determined by the severity and management strategy (outpatient, inpatient with or without ICU admission).

An increase in the number of RSV cases leads to a proportional increase in all components of the burden – direct medical and non‑medical expenditures, indirect costs, and, to a large extent, the value of lost life‑years.

The total socio‑economic burden of RSV infection in children aged 0–2 years (including the value of lost life‑years) is estimated at between RUB 3.31 trillion and RUB 7.01 trillion.

Reducing the socio‑economic burden is possible through preventive measures targeting both the disease itself and its complications, including immunisation. Reducing the budget load, even solely by lowering direct medical costs through effective mass seasonal immunoprophylaxis, especially in infants in the first year of life, could yield substantial economic returns.