Despite the fact that more than a year has passed since the WHO declared the pandemic, there is still no effectivetreatment of COVID-19. According to current knowledge, the only method to stop the virus from spreading is prophylactic vaccination of the population. However, to achieve herd immunity, 60–72% of the population needs to be vaccinated, which is a significant challenge for current healthcare systems. As it has already been proven, having an effective vaccine is not the same as using it. Public acceptance is essential here. The study aimed to assess the changes in the attitudes of online respondents toward vaccination against COVID-19 over time. In the research, a questionnaire designed by the author of the study was used and it was distributed via the Internet in two stages. The questionnaire included a section assessing a sociodemographic status as well as the questions, designed by the author, evaluating the willingness of the respondents to get vaccinated and their main concerns associated with it. The first stage covered the period before the commencement of the population vaccination programme in Poland, i.e., 14–27 December 2020. Then, the survey was redistributed 2 months after the vaccination programme was started, i.e., 1–19 March 2021. Participation in the study was fully anonymous, voluntary and there was a possibility to opt out at any stage of the research. A total of 2048 respondents were surveyed and 26 persons refused to be involved in the research. A total number of 2022 responses were analysed. Stage I of the research involved 22.9% of the respondents (463 persons). The questions were answered by 1559 persons (72.9%) after the survey was redistributed. Among the participants of stage II of the study, 422 (27.1%) persons have already been vaccinated against COVID-19. A comparison of the responses that were collected from both stages of the study showed a slight increase in the willingness to get vaccinated against COVID-19 over time. It turned out that women, residents of large cities, people with a higher level of education and healthcare workers showed a more favourable attitude toward vaccination. According to the results of the survey, chronic diseases do not have a significant impact on the attitude toward vaccinations (p = 0.155). As the social vaccination promotion campaign continued, a slight increase in the willingness to get vaccinated was observed. According to the survey, women, residents of large cities and those with higher education demonstrated more favourable attitudes toward getting vaccinated against COVID-19. It should be stressed that despite the passage of time and the increasing experience with the new types of vaccines against COVID-19, the percentage of people who are afraid of the complications after the vaccination has not decreased significantly and the concern related to the ineffectiveness of vaccination has dramatically increased. This demonstrates the limited effectiveness of the current information system regarding passing the knowledge on of the safety and efficiency of vaccination and it indicates a necessity to modernise it as soon as possible.