Ranking Dynamics of Economic Burden of Infectious Diseases as a Criterion of Effectiveness of Epidemiologic Сontrol экономического от инфекционных

Purpose: rank-based assessment of the economic impact of infectious diseases in the Russian Federation for the further analysis of effectiveness of their prevention and for prioritization of preventive measures. Materials and Methods. The annual economic burden was eStimated by using inflation-adjusted standard economic costs of one case of infectious disease in the Russian Federation. The data on the number of cases were obtained from the official statistical reports (Forms 1, 2) for 2009–2019. The annual burden of the specific disease was estimated by multiplying the standard cost of 1 case by the number of cases registered within a given year. The economic costs were assessed and ranked. Results and discussion. In 2019, the greatest economic burden was exerted by acute respiratory infections, tuberculosis, acute gastrointestinal infections, chickenpox, HIV infection (newly diagnosed cases and deaths in 2019). The economic burden of rotavirus infection was assessed and ranked for the first time. The ranking analysis of the economic costs in 2009–2019 showed the largest decrease in the economic burden of influenza, rubella, acute and chronic hepatitis B. At the same time, the economic burden of measles, pertussis, hemorrhagic fevers and tick-borne borreliosis demonstrated an upward trend. The possibility of using ranking dynamics of economic burden as a performance indicator of epidemiological control has been demonstrated. In response to limited public funding of healthcare, the offered method can be used in setting priorities in decision making in the field of epidemic control. Acknowledgments.


Introduction
Amidst the healthcare reforms unfolding in Russia, the economic analysis comes to the fore, being instrumental in making managerial decisions aimed at achieving maximum effect in disease prevention with limited labor and money resources. The methods of economic analysis can be applied to any healthcare interventions, including prevention techniques, to assess their economic feasibility.
The epidemic control measures, which must be taken in full and on time to prevent any emergence and spread of infectious diseases, include sanitary measures within the Russian Federation, industrial control, restrictive measures (quarantine), isolation of patients with infectious diseases, disinfection measures, preventive vaccination, regular health exams, hygiene education and training, etc. Data resulting from socio-economic impact assessment of a nosological disease are traditionally used for selecting targets in prevention programs of different levels.
The method based on "standard" economic costs of 1 case was offered and adapted to Russia by I.L. Shakhanina [1][2][3][4] for assessment of economic impact of infectious illnesses. Weighted averages of economic burden inflicted by one infectious disease case are quite informative and can serve the purposes of healthcare management [4].
Economic impact is estimated in accordance with GOST R 57525-2017 1 , where "the cost of illness includes all the costs related to treatment of patients with a particular disease, both during a particular stage (period of time) and during all stages of medical care, as well as to disability and premature death". Economic impact of diseases is estimated as burden inflicted on the economy and is measured in rubles.
In the meantime, numerous objective and subjective factors that affect economic costs of each disease, including inflation inputs, make it impossible to provide accurate estimates required for comparative assessment of the economic costs of different diseases in their dynamics. Difficulties associated with the assessment of economic impact of diseases impede the possibility to choose the relevant and most efficient preventive programs to channel the available limited resources.
The purpose of this study is to perform rankbased assessment of the economic impact of infectious diseases in the Russian Federation for the further analysis of effectiveness of their prevention and for prioritization of preventive measures.

Materials and Methods
Standard economic costs of one infectious disease case in Russia were used as inputs for estimation of annual economic burden. Most of the standard economic costs per 1 weighted average case of infectious disease are given in publications of I.L. Shakhanina [2,4]. The economic cost of one disease case was calculated as the sum of direct and indirect costs. The direct costs included the cost of pharmaceuticals, inpatient and outpatient care. The estimation took into account clinical forms broken down by severity. Indirect economic burden was assessed as the gross domestic product unproduced because of labor time (days and years) lost due to an employee's illness or due to the illness of an employee's (acting as a parent or guardian) child. The economic costs of a tuberculosis [5] and HIV infection [6] case were obtained from available publications; costs of rotavirus infection [7], pertussis [8], chickenpox and shingles [9] were calculated during our own studies.
All standard economic costs were adjusted for inflation by using data published by the Russian Federal Statistics Service for the studied time period. The data on the number of cases of infectious diseases were obtained from the publicly available statistical reports (Forms 1 and 2 of the Federal Statistical Monitoring of Infectious Morbidity in the Russian Federation) for 2009-2019.
The annual cost of a single infectious disease was calculated by multiplying the standard economic cost of 1 case of the given disease by the number of cases registered in a particular year. Further on, the economic costs of infectious diseases were ranked in descending order and assessed.
This method was used for the first time by the authors of the article for the State Report on Sanitary and Epidemiologic Well-Being in 2014, and, later on, it was regularly used for state reports of Federal Service for Surveillance on Consumer Rights Protection and Human Well-Being in 2015-2018.
This article analyzes the dynamics of economic cost rankings for specific diseases in 2009-2019.

Results
In 2019, Russia demonstrated a 2.4% decrease in the total number of infectious and parasitic diseases as compared to 2018: The number of registered cases was 34,338,157 cases against 35,166,730 cases in 2018. The growth trend in the incidence of infectious diseases was not pronounced, while the incidence of parasitic diseases declined significantly (Figure). The last 3 years were characterized by a steady downward trend in the incidence of infectious and parasitic diseases.
The performed calculations show that the economic burden resulting from as few as 36 infectious diseases exceeded RUB 646 billion ( Table 1). The economic burden prevented due to decreased incidence of some infectious diseases amounted to around RUB 3.56 billion as compared to 2018. In the meantime, due to the increased number of cases of some nosological diseases, the economic burden increased by more than RUB 7 billion. The absolute economic costs of infectious diseases increased by 1.4% in 2019 as compared to the previous year. When adjusted for the inflation, which, as reported by the Russian Federal Statistics Service 2 , reached 3% in 2019, the total cost of infectious diseases went down by 1.6%.
Following   Table 2) demonstrated the largest decrease in the economic burden resulting from influenza (the ranking changed from the 2 nd to the 11 th ranking position), rubella (from the 25 th to the 30 th position), acute hepatitis B (from the 17 th to the 21 st position) and HBV carrier state (actually, chronic hepatitis B) (from the 12 th to the 17 th position) as well as acute hepatitis A (from ranking 11 th to ranking 15 th ) and shigelloses (from ranking 13 th to ranking 16 th ).
At the same time, the economic burden resulting from measles (down from the 29 th position to the 19 th position) and pertussis (from ranking 22 nd to ranking 13 th ) showed an upward trend. The upward trend was also observed in the economic impact of hemorrhagic fevers (from ranking 14 th to ranking 9 th ) and Lyme dis ease (from ranking 16 th to ranking 12 th ).
As compared to 2018, the ranking results for 2019 showed a decrease in the economic burden of acute and chronic hepatitis C (by 1 and 2 points, respectively), scarlet fever, Lyme disease, diphtheria, tularemia (by 1 point). The economic burden of the following diseases moved up the ranks: hemorrhagic fevers (by 3 points), measles (by 2 points), pertussis (by 1 point).

Discussion
The offered method of ranking costs associated with economic burden gave the possibility to compare not only economic losses caused by different diseases, but also to cross-reference the burden imposed by each nosology within 10 years. The analysis of changes in the rankings of infectious diseases made it possible to assess the effectiveness of ten-year-long control measures taken to fight a particular disease. As expected, the largest reduction of economic burden was achieved in vaccine-controllable infectious diseases -influenza (from 2 nd to 11 th position), rubella (moved down by 5 points), hepatitis B and A (moved down the ranks by 4 points). This fact proves another time that vaccination is the most economically efficient method of epidemic control, in general, and for rubella [10] and hepatitis A [11] and B [12], in particular. As for influenza, the reduction can be also explained by changes in the approaches to case registration -only laboratory-confirmed influenza cases were taken into account during certain time periods [13].
If a disease moves up the ranks in the economic burden ranking list, it may be indicative of existing problems encountered by control measures targeted at a particular infection. For example, the increased eco-nomic burden of measles (up from the 29 th to the 19 th ranking position) results from the recurrence of en demic circulation of measles virus and the increased number of unvaccinated people who contribute to the growing number of infection sites 3 .
The higher ranking positions for the economic burden of pertussis (moving up from the 22 nd to the 13 th position) can be explained by the improved accuracy of infection diagnosis through using more sensitive laboratory techniques and by the increased participation of preschool and school-aged children in spreading of pertussis, thus requiring that the booster vaccination against this infection should be included in the National Immunization Schedule [14,15].
The increased economic impact of hemorrhagic fevers (up from the 14 th to the 9 th ranking position) and Lyme disease (up from the 16 th to the 12 th position) suggests not only the improved accuracy laboratory diagnostic techniques used for the above diseases, but also signifies the need to strengthen the measures aimed at prevention of transmissible infectious diseases amid changing climate conditions, expanding business activities within natural focal spots and decreasing scope of disinfestation measures [16].
The "standard" weighted average economic costs of 1 disease case can be later revised and corrected, taking into account regional specific features, among other things. While previously a number of parameters were estimated for a group of diseases, for example, for acute gastrointestinal infections of known etiology, further estimations will give more accurate profiles for individual infections of the given group. For example, we estimated the burden of 1 case of rotavirus infection [7]. Thus, the burden resulting from this disease was singled out of the combined economic losses caused by the group of acute gastrointestinal infections with the identified pathogen.
Although the burden estimation based on "standard" weighted average economic costs of 1 disease case is clearly not accurate and very rough, it is highly important for planning and prioritizing preventive and anti-epidemic measures targeted at diseases ranking high in economic burden.
The invariably high ranking of the burden caused by chickenpox (ranking 2 nd -3 rd among 33 nosologies in Table 2) emphasizes the urgent need to optimize the infection control, to use the potential of scheduled and emergency preventive vaccination for efficient epidemic control.  2. In response to limited public funding of healthcare, the offered method can be used in setting priorities for preventive and epidemic control measures.