Previous SARS‐CoV‐2 infection is linked to lower vaccination intentions

1.

In their recent communication, Callegaro et al. ¹ could show that mRNA vaccination boosts antibodies elicited by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infections. ¹ Thus, vaccinating not only uninfected but also previously infected individuals could become important for controlling the pandemic. We investigated the vaccination intentions of previously infected, recovered individuals using data from seven cross‐sectional, quota‐representative surveys ² with N = 5692 nonvaccinated German participants, conducted between February 23 and May 19, 2021.1 When asked if they would get vaccinated if they had the chance to do so next week, the vaccination intentions of recovered individuals (n = 276) were lower compared with previously uninfected individuals, Welch's t(304.61) = −3.19, p = 0.002, d = 0.20 (Figure 1). Although confidence in vaccine safety did not differ on the 95% confidence level, Welch's t(305.90) = −1.72, p = 0.086, d = 0.10, previously infected participants rated an infection with SARS‐CoV‐2 as less severe, Welch's t(304.01) = −3.61, p < 0.001, d = 0.22. They also felt less collective responsibility to protect others by getting vaccinated, Welch's t(300.81) = −3.12, p = 0.002, d = 0.20. Both groups were comparable with regard to gender (χ ² (1, N = 5692) = 0.14, p = 0.711) and education (χ ² (1, N = 5692) = 2.53, p = 0.282). However, previously infected individuals were slightly younger than uninfected participants (M = 37.22 vs. 44.57 years; Welch's t(312.63) = −8.66, p < 0.001) and less often suffered from a chronic condition (28% vs. 35%, χ ² (1, N = 5,496) = 5.14, p = 0.023).

Figure 1.

Mean differences between previously uninfected and infected survey participants. Note: Individuals with past natural infection indicated (A) lower vaccination intentions, (B) lower infection severity, and (C) less collective responsibility (i.e., lower willingness to protect others by getting vaccinated), while (D) confidence in vaccine safety was comparable for both groups. All dependent variables were assessed on 7‐point scales ranging from strong disagreement to strong agreement. ³ Error bars visualize 95% confidence intervals

Previously infected people may underestimate the risk of disease because most of them only faced mild to moderate symptoms. ⁴ This explanation is supported by the fact that previously infected individuals were slightly younger and less affected by chronic conditions compared to uninfected participants, two well‐known parameters of infection severity. ⁵ Despite few pieces of evidence on the persistence of natural immunity being available, recovered individuals could further assume they are permanently immune and cannot transmit the disease to others. Although the observed differences were small in our sample and the attitude towards vaccination may depend on individual infection experiences, health preconditions, time passed since the infection, and knowledge, ⁶ even these small differences could become important on the population level as minor changes in vaccination intentions could preclude herd immunity. Thus, this contribution aims at highlighting the fact that coronavirus disease 2019 (COVID‐19) shots for the recovered will be an important topic to consider to reach herd immunity, as barriers to vaccination exist and lacking awareness of being a risk for others and perceiving COVID‐19 as not dangerous may lower vaccination intentions. Consequently, vaccination campaigns and health information should target recovered groups and bolster their vaccination intentions, specifically by highlighting (a) the protecting effect of vaccination for both uninfected and previously infected individuals, (b) the severe consequences of COVID‐19 infections for vulnerable populations, and (c) the severe impact of continued restrictions of social life and health care access for vulnerable individuals, for example, who suffer from cancer or severe mental illness. ⁷ , ⁸

CONFLICT OF INTERESTS

The authors declare that there are no conflict of interests.

ETHICAL DECLARATION

Our research obtained ethical clearance from the University of Erfurt's IRB (#20200302/20200501), and all participants provided informed consent before data collection.

AUTHOR CONTRIBUTIONS

Philipp Sprengholz and Cornelia Betsch designed and performed the research. Philipp Sprengholz planned and performed data analyses. Philipp Sprengholz wrote the initial draft, which was revised and approved by Cornelia Betsch.