The cost of illness for ILI patients presenting in primary care in Germany without a POCT-assisted diagnosis is 87.87 € (see Table 4). The three largest cost factors are additional diagnostics, the first GP visit, and the costs of hospitalization. They add up to 86% of the total costs of illness. This lies within the scope of a prior study calculating the economic burden of influenza in which direct costs added up to an inflation-adjusted 63.03 €26. That study is from 1999 and does not include transport costs or antiviral medication. Using molecular POCT to detect influenza in ILI patients, the direct costs add up to 80.83 € (see Table 4). The first two largest cost factors are the same as those in the clinical judgment approach, but the third one, namely testing costs, is unique to the POCT pathway. Together, the three sum up to 67% of the total costs. Comparing both pathways, 8% or 7.05 € lower costs for patients diagnosed with POCT can be found.

When comparing the costs of illness in detail, a rise in antiviral medication costs of 2.48 € became apparent when using molecular POCT. This result is not surprising since the precise prescription of antivirals is one of the main advantages of using POCT for detecting influenza infection. The opposite effect can be observed with an antibiotic prescription: The costs drop by 1.69 € when POCT is implemented. In relative savings in the number of prescriptions, the additional antivirals are nearly offset by the reduction in antibiotics. In absolute monetary terms, however, antiviral medication is more costly than widely available antibiotics. In addition, targeted use of medication and prevention of unnecessary antibiotic prescriptions may have even a greater benefits than only decreasing health care costs directly, as it helps in reducing the problem of antimicrobial resistance. Other aspects with lower costs on the POCT diagnostic pathway are hospitalizations as well as a reduced volume of additional diagnostics.

The costs of illness differ widely among the age groups (see Tables 5–7 for age-specific results). Using clinical judgment alone, the costs of illness sum up to 155.99 € for elderly people (aged 60+) compared to 76.31 € for adults and 74.15 € for children. With POCT, the costs of illness for elderly people amount to 115,09 €, which is 26% lower than the costs without diagnostic support, as displayed in Table 7. The costs for adults and children, as depicted in Tables 5 and 6, are 74.42 € and 75.66 €, respectively, which means 2.5% lower costs of illness for adults and 2% higher costs for children. For the elderly population, the largest cost factor is hospitalization, and the main cost driver for adults and children is GP visits. Since this visit cannot be reduced with POC diagnostics, the hospitalization rate is lowered for ILI patients when not only using clinical judgment.

Looking at the national level the costs of illness in Table 4 for ILI patients are 800,339,641 € with clinical judgment and 736,143,912 € with POCT assistance based on the patient numbers of the influenza season 2017/18. Taking age into account, the numbers are 145,108,274 € and 148,066,319 € for children, 440,802,489 € and 429,870,865 for adults, and 214,428,877 € and 158,206,728 € for elderly people (Tables 5–7). In total, there are lower costs of 64,195,730 € when using POCT for diagnosing influenza in ILI patients. The largest cost difference lies with elderly patients, with lower costs of 56,222,149 € with diagnostic support.