key: cord-0715575-xhln06n8 authors: Hajek, A.; König, H. H. title: Willingness to pay for SARS-CoV-2 rapid antigen tests during the Covid-19 pandemic. Evidence from the general adult population date: 2022-03-31 journal: Public Health DOI: 10.1016/j.puhe.2022.03.016 sha: bf5ccbfcb7511f000647527864165c02a78019ee doc_id: 715575 cord_uid: xhln06n8 Objective Our aim was to examine the willingness to pay (WTP) for SARS-CoV-2 rapid antigen tests and its correlates during the Covid-19 pandemic in Germany. Study design/Methods: A representative online survey was conducted in late summer 2021 (with n=3,075; average age was 44.5 years; 14.8 years ranging from 18 to 70 years) in Germany. Two-part models were conducted. Various correlates (such as empathy or altruism) were included in regression analysis. Results The average WTP for SARS-CoV-2 rapid antigen tests (in €) was 6.6 (SD: 8.4) in the general adult population. It markedly differed between subgroups (e.g., the average WTP was 2.9 among individuals not vaccinated against Covid-19 and 7.5 among individuals vaccinated against Covid-19; it was 5.4 among the lowest income decile, whereas it was 8.6 among the highest income decile). Regressions showed that a higher WTP for SARS-CoV-2 rapid antigen tests was associated with being male, being in the highest income group, being vaccinated against Covid-19, and higher levels of empathy. Conclusions As the very first study in this area, our study described WTP for SARS-CoV-2 rapid antigen tests and some interesting differences between population subgroups. In particular, individuals not vaccinated against Covid-19 reported a low WTP for SARS-CoV-2 rapid antigen tests. About one quarter of the sample reported a WTP for SARS-CoV-2 rapid antigen tests of €0 among individuals vaccinated against Covid-19, whereas about two thirds of those not vaccinated against Covid-19 reported such a WTP. Knowledge about the WTP for Covid-19 rapid antigen tests is important for policy makers (e.g., for testing strategies) during this pandemic. It may also give a rough estimation of the acceptance of such rapid tests. Since March 2020, individuals in Germany have been contending with the consequences of the ongoing Covid-19 pandemic. A few months after the start of the pandemic, tests (e.g. PCR tests) were used to quickly identify infected persons and put in place appropriate measures (e.g. isolation and tracing of contact persons) 1, 2 . Later in 2020, SARS-CoV-2 rapid antigen tests (and also self-tests) became available in Germany. Many Corona rapid testing centres opened in Germany in spring 2021, with many testing options being relatively quick, widespread and relatively inexpensive. Such testing services are perceived as having great potential in the global fight against the pandemic 3, 4 . There are some studies on readiness for a Covid-19 vaccine in Germany (for example [7] ). These studies also showed a high readiness for rapid testing (from December 2020 to March 2021) [5] . For example, the likelihood of using such a test was positively associated with low price and ease of use [5] . Moreover, while various studies in different countries and subgroups examined the willingness to pay (WTP) for a (hypothetical) Covid-19 vaccine [5] [6] [7] [8] [9] [10] [11] , there are not currently any studies regarding the WTP for SARS-CoV-2 rapid antigen tests (in Germany and also globally). Generally, a WTP refers to a maximum amount of money an individual is willing to spend for a certain product or service 12 . Such knowledge is important for policy makers (e.g., for testing strategies) during the Covid-19 pandemic. Moreover, knowledge about the WTP for SARS-CoV-2 rapid antigen tests may give a rough estimation of the acceptance of such rapid tests in the general adult population and in certain subgroups (such as individuals not vaccinated against Covid-19). Thus, our aim was to examine the WTP for SARS-CoV-2 rapid antigen tests and its correlates in Germany in late summer 2021. It is worth noting that during the time of data collection (late August to early September 2021), such rapid tests were free of charge in Germany. However, during that time, the German J o u r n a l P r e -p r o o f government had already announced that such rapid tests would no longer be free of charge from October 2021. The data came from a representative online survey of 3,075 adults in Germany aged 18 to 70. Only people aged younger than 18 or older than 70, as well as those who did not live in Germany, were excluded. It should be noted that the questionnaire was only available in German. Fieldwork took place from late August to early September 2021. The individuals were recruited by a well-known market research institute using its own online access panel. Individuals were drawn from this online sample in such a way that they reflected the distribution of gender, age bracket, and federal state in the German adult population [13] . Quotas were derived from Best for Planning 2020. An invitation to participate was sent to approximately 14,000 individuals. Since this was an online-survey, potential differences between respondents and non-respondents could not be examined. With regard to the representativeness, for example, in the German Socio-Economic Panel (GSOEP), the median household net income was similar compared to our study (GSOEP: about 2,200 Euro in the year 2018 (continuously assessed) vs. in our study: 2,500-3,000 Euro (income category; late Summer 2021) 13 . Moreover, the proportion of unemployed individuals was 5. Hamburg-Eppendorf approved the study (number: LPEK-0356). Individuals self-reported the WTP for SARS-CoV-2 rapid antigen tests (in €). It was introduced as follows: "Currently, the costs for rapid tests are covered by the state. From October, the rapid tests for the unvaccinated will no longer be free of charge. What is the maximum amount you would be willing to pay for such a rapid test?" (options: €0; €5; €10; €15; €20; €25; €30; €35; €40; more than €40). Values of "more than €40" were transformed to €45 to calculate an average WTP. It should be noted that two concepts exist to calculating WTP: Revealed preferences and stated preferences. Revealed preferences can be quantified by using, for example, natural field experiments or lab experiments. In contrast, stated preferences can be quantified using indirect surveys (e.g., conjoint analysis) or direct survey approaches. In our study, the stated preference concept via a direct survey approach was applied. In regression analysis, we included the following factors as correlates: Sex (women; men; diverse), age, presence of at least one child in own household (no; yes), marital status (married, Moreover, we included empathy (ability to imagine what life is like for another individual 15 ) and altruism (referring to disinterestedness and selflessness 16 ). Based on the short scale of the Interpersonality Reactivity Index (IRI 15 ; German version: Saarbrucken personality questionnaire, SPF 17short version: SPF-K), empathy was assessed. This tool consists of four items 18 . A sum score was calculated (which ranges from 4 to 20, higher reflect correspond to higher levels of empathy). Cronbach's alpha was .81 in our study. The subscale 'altruism' of the International Personality Item Pool (IPIP-5F30F-R1 19 ) was used which consists of six items. All items were recoded. Thereafter, the score was generated by averaging all items (ranging from 1 to 5, with higher values reflecting higher altruism). Cronbach's alpha was .87 in our study. Initially, the average WTP for SARS-CoV-2 rapid antigen tests in Euro was displayed (total sample and by some subgroups). Thereafter, two-part models 20 were conducted to analyze the correlates of WTP for SARS-CoV-2 rapid antigen tests (first part: logit model; second part: generalized linear model with gamma distribution and log link function; taking into account the skewed distribution of positive values 21 ). Such models are frequently used when the proportion of zero values is large (i.e., absence of WTP for SARS-CoV-2 rapid antigen tests in our study). The "twopm" command in Stata was used to conduct the two-part models 20 . We calculated average marginal effects due to ease of interpretation. They indicate the change in WTP for SARS-CoV-2 rapid antigen tests (in €) associated with a one unit change in the correlates (or the difference to the reference category -in the case of categorical variables). Statistical significance was defined as p value of 0.05 or smaller. Stata 16.1 (Stata Corp., College Station, Texas) was used to conduct statistical analyses. In our total sample, the average age was 44.5 years (SD: 14.8 years). It consisted of 51.1% female individuals. In Supplementary Table S1 , we provide a comparison of our sample and the target cohort (sex, age group and state). The average WTP for SARS-CoV-2 rapid antigen tests (in €) is shown in Table 1 (total sample and stratified by subgroups). In the total sample, average WTP for SARS-CoV-2 rapid antigen tests (in €) was 6.6 (SD: 8.4). In the subgroups, the average WTP for SARS-CoV-2 rapid antigen tests (in €) ranged between 2.9 (among individuals not vaccinated against Covid-19) and 7.5 (among individuals vaccinated against . Further details are given in Table 1 To check for multicollinearity, we calculated the variance inflation factors. The highest variance inflation factor (VIF) was 2.7 (highest income group), with an average VIF of 1.4indicating that multicollinearity is not a threat. Two-part models are displayed in Table 2 . It is worth repeating that the first part refers to a logit model and the second part refers to a generalized linear model with gamma distribution and log link function. The likelihood of reporting a WTP for SARS-CoV-2 rapid antigen tests higher than zero (first part: logit model) was positively associated with a high educational level, being in the highest income decile, being vaccinated against Covid-19 and having a higher empathy level. The extent of WTP (conditional on a WTP for SARS-CoV-2 rapid antigen tests higher than zero; second part) was positively associated with being male and being vaccinated against Covid-19. Additionally, average marginal effects (last column in Table 2 ) showed that higher WTP for SARS-CoV-2 rapid antigen tests was significantly associated with being male, being in the highest income decile, being vaccinated against Covid-19 and higher levels of empathy. Using data from the general adult population in Germany, this is the very first study quantifying the WTP for SARS-CoV-2 rapid antigen tests and its correlates during the Covid-19 pandemic and consequently forms a basis for future research. It should be emphasized that rapid test centers charged around 15 € for SARS-CoV-2 rapid antigen tests in Germany in October 2021. However, due to the increase in the number of cases, these SARS-CoV-2 rapid antigen tests are already free of charge again (mostly since November 2021). Compared to other groups, particularly individuals not being vaccinated against Covid-19 reported a rather low WTP for SARS-CoV-2 rapid antigen tests. Additionally, regressions showed that a higher WTP for SARS-CoV-2 rapid antigen tests was associated with being male, being in the highest income decile, being vaccinated against Covid-19 and higher levels of empathy. It appears to be plausible for us that not being vaccinated against Covid-19 was associated with much lower levels of WTP for SARS-CoV-2 rapid antigen tests in our study. Findings from the European COvid survey (September 2021) showed that different reasons for not getting vaccinated against Covid-19 exists in Germany such as that the respondents did not want to support the profit-striving of global vaccine producers or they did not think that Covid-19 vaccines are safe enough 22 . These reasons may also reflect that such individuals also do not want to support manufacturers of rapid tests and do not have much trust in the accuracy of such rapid tests. This could be a politically important outcome: The fact that they have to pay for such tests is probably a deterrent to testing, particularly for the individuals not being vaccinated against Covid-19, for whom the tests are likely most important. Those who refuse vaccination probably see less danger in infection. However, future research is required to elucidate the underlying mechanisms. Moreover, individuals in the highest income decile reported a higher WTP for SARS-CoV-2 rapid antigen tests in our study compared to individuals in the lowest income decile. Such income discrepancies may particularly reflect differences in financial opportunities. Moreover, such individuals in the highest income decile may have a higher trust in the accuracy of such rapid tests compared to individuals in the lowest income decile and may thus report a higher WTP for SARS-CoV-2 rapid antigen tests. Our study also showed an association between higher empathy and a higher WTP for SARS-CoV-2 rapid antigen tests. Such a link appears quite plausible because empathy is also positively associated with prosocial behavior such as donating blood 23 , and also wearing face masks during the pandemic 24 . Individuals scoring high in empathy may therefore appreciate rapid tests due to their potential in the fight against Covid-19. Surprisingly, altruism was only marginally significantly associated with a higher likelihood of reporting a WTP for SARS-CoV-2 rapid antigen tests higher than zero. Future research is required to clarify this association in further detail. Some strengths and limitations of our current study are worth acknowledging. This is the very first study quantifying the WTP for SARS-CoV-2 rapid antigen tests during the pandemic. Data were taken from a large, representative study. However, the questionnaire was only available in German language. Thus, it is very likely that individuals with a migration background are underrepresented. Moreover, the general possibility of an online bias cannot be dismissed. Established tools were used to quantify the correlates. A single-item was used to assess WTP (preference concept via a direct survey approach was applied). Advantages of such an assessment include its high face validity, as well as its simple and efficient assessment of WTP. However, further research with more sophisticated tools to measure WTP is desirable since such direct survey approaches may lead to the true WTP is not being identified. For example, indirect survey methods such as conjoint analyses or discrete choice analyses could be used. Moreover, further research is required using data from the oldest old because our study only included individuals 18 to 70 years. Additionally, longitudinal studies are required to confirm our findings. In conclusion, our study revealed the WTP for SARS-CoV-2 rapid antigen tests and some interesting differences between subgroups. Particularly individuals not being vaccinated against Covid-19 reported a low WTP for SARS-CoV-2 rapid antigen tests. About one fourth J o u r n a l P r e -p r o o f reported a WTP for SARS-CoV-2 rapid antigen tests of €0 among individuals being vaccinated against Covid-19, whereas about two third reported such a WTP among individuals not being vaccinated against Covid-19. Knowledge about the WTP is important for policy makers (e.g., for testing strategies) during this pandemic. It may also give a rough estimation of the acceptance of such rapid tests. 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