Croatia Reports Fewer Vaccine Side Effects in 2024, HPV Vaccine Leads Reports

Croatia recorded 63 suspected adverse reactions following vaccinations in 2024, marking a decrease from the 83 reports logged in 2023. Data from the Croatian Institute of Public Health (HZJZ) indicates that the majority of these reactions were mild and temporary, including common responses like pain or swelling at the injection site, slight fever, rash, and dizziness.

Of the total reports, 27 were related to vaccines administered under the Mandatory Vaccination Program, covering immunizations against measles, mumps, rubella, polio, diphtheria, tetanus, and pertussis. The remaining 36 reports were associated with vaccines outside this program. Notably, the HPV vaccine, particularly the nine-valent Gardasil 9, generated the highest number of individual reports, with 15 cases. Six additional reports involved Gardasil 9 administered concurrently with a diphtheria, tetanus, and polio vaccine.

While the Gardasil 9 vaccine saw the most individual reports, the HZJZ cautions that the number of reports alone does not reflect the actual frequency of side effects. The report does not provide data on the number of vaccine doses administered, making direct comparisons of incidence rates impossible. For Gardasil 9, reported reactions included local effects, fever, hives, dizziness, weakness, and nausea. One case involved a suspected epileptic seizure immediately after vaccination, requiring further medical observation.

The HZJZ emphasizes that a reported health issue following vaccination does not automatically mean the vaccine caused it. The registry primarily serves to identify unexpected reactions or changes in reaction frequency that might warrant further investigation. The decrease in reported cases suggests either a genuine reduction in adverse events or, more likely, that mild and expected reactions are often not reported, as they are considered normal responses to vaccination.