Study: COVID-19 Boosters Associated with More Flu-like Illness and Sick Leave

There are no few studies that show the lack of long-term benefits and even harm from the COVID-19 “vaccines”. However, some data indicate short-term protection even if it wanes.

A Swiss study by T. Dörr et al titled “Association of SARS-CoV-2 vaccination status with risk of influenza-like illness and loss of workdays in healthcare workers” published on 9 August 2025 has found that the jabs didn’t even provide short-term benefit. The paper is 8 pages long, including references.

The study collected or updated baseline data from the participants in October 2023. This was followed by weekly questionnaires from 1 November 2023 to 30 April 2024 in which participants reported any of the 22 respiratory, gastrointestinal and general symptoms with an acute onset, amongst other details. Only participants who answered at least 50% of the questionnaires were included and those who received more than 4 doses were excluded.

Of 2113 HCW who filled in the baseline questionnaire in September 2023, 1745 (82.6%) were included, with a median age of 46 years (range 17–70) and 81.6% being female.

Of the 1,745 participants, 895 (51.3%) reported receiving 3 doses, the largest group. The smallest group was the unvaccinated, of which there were 175 (10.0%). The majority of the vaccinated received their last dose at least one year previously.

In short, those who received boosters were more likely to suffer influenza-like respiratory illness (ILI) and take sick leave, which is not the case for those who receive seasonal flu vaccines. Perhaps surprisingly, those involved in direct patient care reported fewer days of sick leave despite having no difference in the number of ILI experienced.

Overall, 853 (48.9%) reported at least one day of absence due to ILI symptoms, with the majority (76.6%) being on sick leave for several days. In univariable analysis, vaccination status with 3 and 4 doses was significantly associated with the number of ILI (IRR 1.34, 95% CI 1.05–1.74 and 1.41, 95% CI 1.06–1.87 respectively), and, for 3 doses also with workdays lost (IRR 1.38, 95% CI 1.01–1.85).

Figure 2: Participants experiencing ILI episodes and workdays lost during follow-up per vaccination group.

The below from the discussion sums it up well:

SARS-CoV-2 vaccination was not associated with a protective effect against ILI. On the contrary, we observed a clinically relevant risk of ILI with up to 70% increase. This is in line with a number of recently published studies that focused on the risk of SARS-CoV-2 reinfection as outcome. They reported hazard ratios between 1.4 and 3.6 for people with vs. those without (or less doses of) SARS-CoV-2 vaccine. In our data, this risk association was stronger with a more recent vaccination than with the number of doses received, suggesting the association to be temporary and to wane over time.

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