Implementation of the preventive vaccination program in the time of the COVID-19 pandemic - single center study.

Introduction: In addition to many diagnostic and therapeutic procedures, the COVID-19 pandemic also limited prophylaxis, including the implementation of the vaccination program among children.

Objective: The aim of the study was to assess the implementation of the vaccination program in the area covered by the care of patients of a selected Primary Health Care clinic in the city of Krakow in the field of selected vaccinations during the COVID-19 pandemic.

Material and methods: A retrospective study based on secondary data was conducted in a selected clinic (Kraków, Poland) that cares for 1,982 children aged 0-19 years. An analysis of the vaccination coverage in selected groups of children in 2019, 2020 and 2021 was carried out based on annual reports (MZ-54). Vaccination coverage against: diphtheria, tetanus, whooping cough, measles, mumps, rubella, influenza and pneumococcal infection was analyzed. The collected data were analyzed using descriptive statistics, Chi2 test and Fisher's exact test.

Results: In the general vaccination status of two-year-olds, no significant differences were observed in the period 2019-2021 (p=0.156). The percentage of fully vaccinated increased from 77.6% in 2019, to 81.5% in 2020 and to 85.2% in 2021. However, a high rate of vaccination refusals was observed in 2021 (4.1%) in this group. The percentage of 2-year-olds vaccinated against pneumococci (PCV) and 3-year-olds against diphtheria, tetanus, pertussis (DTP), and measles, mumps, rubella (MMR) in the years 2019-2021 was increasing. For DTP and MMR, this increase was significant (p<0.05). In the group of older children, in 2020 the percentage of 7- and 15-year-olds vaccinated decreased compared to 2019 and 2021, but the difference was insignificant (p>0.05). A significant difference in vaccination coverage was observed in the group of 19-year-olds, in which in 2020 the percentage of vaccinated was 58% (in 2019 - 74.6%, in 2021 - 81%). The largest number of children under the age of 5 were vaccinated against influenza in 2021, but it was only less than 2% of this group.

Conclusions: Sanitary restrictions introduced during the COVID-19 pandemic did not significantly affect the vaccination status of children in selected age groups against the analyzed vaccine-preventable diseases. The exception is the group of 19-year-olds, whose vaccination coverage in 2020 was much lower than in 2019 and 2021. In addition, an increase in refusals of vaccination was observed, reaching 4.1% in 2021 in the group of the youngest patients.