Evaluation of Coverage Rates of 3 Pediatric Vaccines (Measles-Mumps-Rubella, Hexavalent, and Varicella) in a Southern Italian Province (2016–2022): Effect of the Pandemic and Interregional Comparisons

Introduction

Vaccination is a fundamental tool against infectious diseases and one of the most important prevention measures for public health [1]. In 1888, the first Italian law (Law No. 5849/1888) introducing mandatory vaccination against smallpox for all newborns within the first year of life was passed. It was a response to the serious epidemic that had affected the country, and the law required children to be vaccinated against this highly contagious and often lethal disease. The law also provided for sanctions for those who did not undergo vaccination [2,3].

Mandatory vaccination was extended to diphtheria in 1939 (Law No. 891/1939) and to polio in 1966 (Law No. 51/1966). This was a measure aimed at strengthening the national immunization program and combating the spread of diseases that had a major effect on public health [4]. In Italy, the first recommendations for pertussis vaccination date back to 1961, with the introduction of whole-cell vaccines. However, vaccination coverage increased significantly only from 1995, with the introduction of acellular pertussis vaccines, and was further consolidated after 2002, when the vaccine was made available free of charge in all Italian regions [5].

Since the 1990s, vaccination has seen significant changes. Legislation has adapted to new scientific discoveries, and the introduction of new vaccines has led to a review of regulations [6]. One of the most important innovations was the introduction of the hepatitis B vaccine in 1991 [7]. Since the 2000s there has been a decline in vaccination coverage and a resurgence of preventable diseases, particularly measles. Several studies have highlighted factors that influence adherence to pediatric vaccinations, in particular for measles-mumps-rubella (MMR). These include vaccine hesitancy associated with concerns about a purported association between MMR vaccination and autism, mistrust in health institutions, exposure to anti-vaccination content, organizational barriers, such as difficulty in accessing services, or limited active supply. Unfavorable socioeconomic conditions have also been associated with lower vaccination coverage, contributing to the variability observed in different high-income contexts. Some studies have also found that the level of education and ethnicity of parents can influence parents’ ideology regarding the vaccination of their children [8–10].

These developments caused the legislator to introduce, in 2017, Law No. 119/2017 [11], which made 10 vaccinations mandatory for children, including those against measles, mumps, rubella, polio, diphtheria, tetanus, pertussis, hepatitis B, Haemophilus influenzae type b, meningococcus B and C, pneumococcus, and varicella (chickenpox) [12]. This law also led to the official adoption, again in 2017, of the Calendar for Life, which includes all mandatory and recommended vaccinations for the population. Each Italian region then implemented the calendar at a local level, adapting it to the specific health and organizational needs of the area [13]. In the Campania region, one of the most populous in Italy, vaccination services are provided through an extensive network of dedicated clinics present in the various health districts of the 7 local health authorities [14].

In this well-established context, the emergence of the COVID-19 pandemic introduced new and unforeseen challenges to immunization programs [10,15]. COVID-19, first identified in Wuhan, China, in December 2019, rapidly evolved into a global health emergency [16]. Caused by the SARS-CoV-2 virus, COVID-19 primarily spreads through respiratory droplets and can lead to a broad spectrum of symptoms, from mild respiratory distress to severe complications, such as pneumonia, respiratory failure, and acute respiratory distress syndrome, especially among older adults and individuals with underlying health conditions [17]. The World Health Organization (WHO) declared COVID-19 a global pandemic in March 2020. In response, governments worldwide implemented emergency measures, such as lockdowns, social distancing, and mass vaccination campaigns [18]. These interventions had a significant effect not only on people’s mental health [19] but also on the accessibility and continuity of routine health services, including vaccination programs. During the lockdown phases, many vaccination centers reduced their activities or temporarily closed, which, along with public fear of infection and concerns of vaccine safety, contributed to a decline in pediatric and adult vaccination coverage [20].

During the COVID-19 pandemic, several factors contributed to changes in routine immunization coverage. The implementation of national lockdowns and mobility restrictions led to the temporary suspension or reduced operation of many vaccination centers, particularly during the first epidemic waves. In addition, widespread public concern about exposure to SARS-CoV-2 in healthcare settings resulted in postponed appointments and missed vaccination opportunities. In Italy, these disruptions varied across regions, depending on organizational capacity and local epidemiological conditions. To mitigate these effects, national and regional health authorities introduced specific interventions, including the re-scheduling of vaccination appointments, extended clinic hours, call-and-recall systems targeting children with incomplete vaccination status, and the integration of pediatric vaccination activities into primary care and community health networks. In the Campania region, targeted catch-up campaigns were implemented starting in late 2020, contributing to the recovery of vaccination coverage rates observed in the subsequent years [21,22]. Alongside the experience in Italy, several international studies documented similar patterns in routine immunization during the COVID-19 pandemic, demonstrating that the disruptions observed in Italy were part of a broader global phenomenon. In Europe, temporary declines in childhood vaccination coverage were reported in France, Germany, and the United Kingdom, particularly during the first lockdowns, although partial increases were seen following the implementation of targeted catch-up strategies. In the United States, routine pediatric vaccination rates decreased substantially during the early months of 2020, with some states reporting reductions of up to 20%. Low- and middle-income countries experienced even more pronounced drops, often associated with health system fragility, reduced mobility, and interruptions in vaccine supply chains. According to WHO and UNICEF estimates, over 25 million children worldwide missed at least 1 essential vaccine dose in 2021, the highest figure recorded in nearly a decade. These global findings underscore the widespread vulnerability of immunization programs during health emergencies, while also highlighting the importance of resilient health systems and timely mitigation strategies to safeguard routine vaccination coverage.

Therefore, evidence from other countries highlights the importance of implementing flexible and resilient immunization strategies during health emergencies. These include the integration of vaccination activities into community care pathways, reinforcement of digital reminder-recall systems, prioritization of catch-up programs for missed doses, and adoption of targeted communication campaigns to counter vaccine hesitancy–related misconceptions. Lessons learned from the COVID-19 pandemic suggest that investing in stronger primary care networks, interoperable immunization registries, and standardized emergency operating procedures can help safeguard essential services, such as routine childhood vaccination.

In this context, monitoring vaccination coverage trends is essential for assessing the resilience of local health systems during public health emergencies [22]. This study was designed to investigate whether the COVID-19 pandemic affected routine childhood vaccination coverage in a province of southern Italy. We hypothesized that the pandemic would lead to a temporary reduction in vaccination uptake, primarily due to reduced access to healthcare services, parental concerns about exposure to SARS-CoV-2, and the reallocation of public health resources toward pandemic response. We also expected that, following service reorganization and catch-up strategies, coverage rates may recover in the subsequent phase. Building on these premises, the present study analyzes vaccination coverage across all health districts of the province of Salerno over a 7-year period, comparing pre-pandemic (2016–2019) and pandemic (2020–2022) trends and contextualizing them within national and international patterns. In doing so, the study provides novel insights into how local organizational strategies may mitigate service disruptions and maintain high immunization rates even under crisis conditions. These findings contribute to the broader global discussion on strengthening health system preparedness and ensuring the continuity of essential preventive services during future public health emergencies

Previous research on vaccination trends during pandemics has been limited by the use of aggregated data, limited socioeconomic stratification, and the absence of longitudinal follow-up capable of capturing post-pandemic recovery patterns. Few studies have examined disparities across local health districts or investigated behavioral determinants, including parental hesitancy and access barriers. To address these gaps, future investigations should focus on individual-level determinants of missed vaccinations, the role of digital health tools in improving adherence, and the long-term structural effects of pandemics on immunization infrastructures. Our study contributes to this growing body of evidence by providing multi-year, district-level data from a large Italian province.

Material and Methods

STUDY DESIGN AND SETTING:

We conducted a retrospective population-based observational study using administrative vaccination data collected from the Sinfonia portal, the official digital health information system of the Campania region. This study was conducted in the province of Salerno, located in the Campania region of Southern Italy. It included vaccination data from all health districts in the province, collected over a 7-year period (2016–2022).

STUDY POPULATION:

The study population included all children residing in the province of Salerno who were eligible for mandatory vaccinations between 2016 and 2022, according to the national immunization schedule. Eligibility was defined according to the national immunization schedule for each vaccine, which establishes administration in early childhood. Included children were those aged within the recommended vaccination windows (typically 13–15 months for MMR and varicella, and the first months of life for the hexavalent vaccine) who were officially registered as residents in the province of Salerno for the entire period relevant to vaccine administration. These cohorts received the hexavalent, MMR, and varicella vaccines during early childhood as part of routine pediatric immunization programs.

POTENTIAL CONFOUNDING FACTORS:

Potential confounding factors were analyzed, including (1) demographic changes in the 0- to 24-month-old population of the province of Salerno; (2) aggregate socioeconomic indicators (unemployment rate, average per capita income, social vulnerability index); and (3) any changes to regional and national vaccination policies. The analyses are based on ISTAT data and regional documents relating to the organization of vaccination services. No substantial changes were detected in these variables in the period from 2016 to 2022.

DATA ANALYSIS:

For analytical purposes, the observation period was divided into 2 phases: the pre-pandemic period (2016–2020) and the pandemic period (2020–2022), corresponding to the years before and after the onset of the COVID-19 pandemic. The vaccines analyzed were the hexavalent vaccine, which protects against diphtheria, tetanus, pertussis, polio, hepatitis B, and Haemophilus influenzae type b; the MMR vaccine, against measles, mumps, and rubella; and the varicella vaccine. This study focused exclusively on mandatory vaccinations introduced by Law No. 119/2017. Specifically, we analyzed coverage rates for (1) the hexavalent vaccine, (2) the MMR vaccine, and (3) the varicella vaccine. Recommended, non-mandatory vaccines were not included. Coverage was evaluated in pediatric cohorts at the ages scheduled for routine administration according to the national immunization calendar, which remained consistent throughout the study period.

Data were preliminarily organized in Microsoft Excel; however, all statistical analyses were performed in R (version 12.1.4), ensuring full accuracy and reproducibility. To evaluate any relationships between the variables, the chi-square test was used to determine the existence of a statistically significant association. Given the aggregated structure of the dataset, regression-based modeling approaches, such as logistic regression or generalized linear mixed models, could not be applied because they require individual-level data. For this reason, the chi-square test was selected as the most appropriate method for comparing annual vaccination coverage. The significant temporal increase observed for varicella coverage was evaluated using the Cochran-Armitage test for trend (P<0.001). No correction for multiple comparisons was applied, as each vaccine was analyzed independently. Analyses were conducted with R 4.3.1. Linear trend tests and linear regression interrupted time series analysis were applied to evaluate immediate and trend changes associated with the onset of the pandemic (March 2020). The 95% CI and effect size (Cohen’s d) were calculated.

The primary outcome variable in this study was vaccination coverage, defined as the percentage of children who completed the full vaccination schedule for a given vaccine (hexavalent, MMR, varicella) in a specific year, calculated as:

No missing data were identified in the administrative dataset, as the regional registry automatically flags incomplete records. Therefore, no imputation procedures were required.

LIMITATIONS:

This study has several limitations. First, the data used were aggregated and derived from administrative sources, which did not allow for stratification by additional demographic or socioeconomic variables that may influence vaccination uptake. Residual misclassification of vaccination status cannot be entirely excluded, despite periodic quality controls performed by the regional registry. Second, the analysis was limited to a single province in southern Italy; therefore, while comparisons were made with regional and national data, the findings may not be generalizable to other contexts with different healthcare structures or vaccination policies. Lastly, the reasons for missed or delayed vaccinations could not be assessed, as this information is not available in the data source used. This represents a further important limitation, as the administrative dataset does not include information on behavioral, organizational, or contextual factors – such as parental hesitancy, logistical barriers, temporary service disruptions, or medical contraindications – that may explain why vaccinations are missed or postponed. As a result, the study cannot determine whether fluctuations in coverage are driven by individual choices, system-level constraints, or pandemic-related dynamics, nor can it identify specific subgroups at higher risk of under-vaccination. Future research should integrate administrative data with primary data collection (eg, surveys or interviews) or with more granular information systems to better understand the determinants of missed vaccination opportunities.

The use of administrative data can introduce several forms of bias. First, although the regional information system systematically records all vaccinations performed, a residual risk of selection bias can persist if some vaccinations administered outside the regional system were not captured. Second, information bias can arise from delays, inaccuracies, or inconsistencies in data entry, even if periodic data quality checks conducted by the regional platform help minimize these errors. Finally, the use of aggregated data prevents adjustment for potential confounding variables, such as socioeconomic status, parental education, or differential access to healthcare services, which can influence vaccination uptake. These limitations do not alter the descriptive nature of the study but should be considered when interpreting the findings. The aggregated nature of the data also prevented the use of regression-based or mixed statistical models, which would require individual-level covariates.

A further limitation concerns the generalizability of the findings. Because the study focuses on a single province within the Campania region, the results may not be directly applicable to areas characterized by different healthcare structures, organizational models, or vaccination policies. Variations in service accessibility, digital immunization registry implementation, parental attitudes, and local health governance can influence vaccination uptake and thus limit external validity. Future studies should incorporate multicentric data, include comparisons across regions with diverse organizational frameworks, and, where possible, analyze individual-level determinants to better understand the factors that drive variability in vaccination coverage across different contexts.

Furthermore, more advanced statistical techniques, such as time-series analysis or interrupted time-series models, could provide a deeper understanding of the causal impact of the pandemic on vaccination coverage. Future research could incorporate these methods to complement the descriptive approach adopted in the present study.

For interregional comparison, vaccination coverage in the province of Salerno was evaluated alongside coverage at the regional level (Campania), national level, and in selected regions (Lazio, Sicily, and the autonomous province of Bolzano), which were chosen due to their distinct epidemiological and organizational vaccination contexts. Data were obtained from official surveillance reports issued by the Italian Ministry of Health and Istituto Superiore di Sanità. These comparisons were descriptive and conducted using aggregated data; therefore, adjustments for potential confounders, such as socioeconomic status, urban versus rural distribution, or healthcare service accessibility, were not possible.

ETHICAL CONSIDERATIONS:

This study used anonymized and aggregated vaccination data retrieved from Sinfonia portal, the official digital health information system of the Campania region. No personal identifiers were accessible to the researchers at any stage. As the study relied exclusively on routinely collected administrative data, without involving direct contact with individuals, informed consent was not required according to the EU General Data Protection Regulation (Regulation EU 2016/679) and relevant Italian legislation on the use of health data for research and public health monitoring. The use of anonymized administrative datasets for epidemiological analysis complies with national and regional data protection policies.

Results

VACCINATION COVERAGE AND POPULATION INDICATORS:

The study analyzed the vaccination coverage recorded in the health districts of the local health authority of the province of Salerno from 2016 to 2022 for the following vaccinations: diphtheria, tetanus, pertussis, polio, hepatitis B, Haemophilus influenzae type b infections, measles, mumps, rubella, and varicella. The trends in vaccination are stated below. The 0- to 24-month-old population of the province of Salerno remained relatively stable (total change: −1.8% from 2016 to 2022). Even the provincial socioeconomic indicators do not show significant changes.

HEXAVALENT VACCINE COVERAGE:

Vaccination coverage for the hexavalent vaccine given with 3 doses is sustained at a high level throughout the study period. In 2016, the coverage for the hexavalent vaccine was 94.35%, in 2017 it reached 95.02%, and in 2018 there was an increase to a peak of 95.51% while in 2019 and 2022 they stood at 95.23% and 95.21% respectively. However, a slight decline was observed in 2020 and 2021, with values of 94.54% and 94.58% respectively.

MMR VACCINE COVERAGE:

Regarding vaccination for measles, mumps, and rubella, typically administered around 13 to 15 months of the child’s life, a more marked growth trend was observed. In 2016, vaccination coverage of 87.75% was observed, but in the following years, a progressive improvement was observed: the coverage rose to 91.26% in 2017, to 93.10% in 2018, and to 93.23% in 2019 and 2020, remaining at similar values also in the following 2 years, at 93.26% in 2021 and 93.00% in 2022.

VARICELLA VACCINE COVERAGE:

Vaccination coverage of the varicella vaccine was lower at the beginning of the study period and then showed a statistically significant increase (P<0.001) in the following years. (Additional statistical parameters for all vaccines, including confidence intervals and effect sizes, are reported in Table 1). In fact, the coverage was 67.26% in 2016; 75.91% in 2017; 81.66% in 2018; up to 88.00% in 2019; and 89.21% in 2020. A clearer improvement was recorded in 2021, with a coverage of 91.00%, which was also kept stable in 2022. The graph clearly documents the maintenance of vaccination coverage. Overall, all curves show a tendency to stabilize at values close to or above 90%, consistent with regional coverage targets (Figure 1).

INTERRUPTED TIME SERIES ANALYSIS:

The interrupted time series analysis showed a significant reduction in 2020 (P<0.05), followed by a recovery already in 2021, with no evidence of negative delayed effects in 2022.

ANNUAL NUMBER OF VACCINE ADMINISTRATIONS:

The graph in Figure 2 shows the annual comparison of the total number of vaccinated persons for each vaccine. A constant and progressive increase is observed for all the types considered, with a peak in the number of administrations reached in the last 2 years. The hexavalent vaccine is consistently confirmed as the one with the highest number of vaccinated, rising from about 4961 administrations in 2016 to over 6445 in 2022, with a particularly marked increase in the 3-year period from 2018 to 2020. The measles-mumps-rubella vaccine shows a parallel trend to the hexavalent vaccine, with slightly lower values, increasing from about 4614 vaccinated in 2016 to more than 6296 in 2022. The varicella vaccination, on the other hand, shows an even clearer upward trend, starting from a significantly lower number of administrations, about 3536 in 2016, and reaching more than 6160 vaccinated in 2022, almost completely narrowing the gap with the other vaccines.

EFFECT OF THE COVID-19 PANDEMIC ON VACCINATION ACTIVITY:

A summary of the vaccines administered during the 2020–2022 pandemic period, their target age groups, and delivery channels is provided in Table 2.

Overall, the data presented in Figure 3 indicate that the pandemic did not lead to a persistent decline in pediatric vaccinations, but on the contrary, the subsequent period was characterized by an average increase in administrations for all vaccine types considered.

Discussion

In this study, we analyzed vaccination coverage for the hexavalent vaccine, MMR vaccine, and varicella vaccine in the province of Salerno in the period from 2016 to 2022. Coverage for the hexavalent vaccine remained stably high throughout the period, coverage for MMR showed a progressive increase and subsequent stabilization above 93%, while coverage for varicella showed the most marked improvement, going from 67% to over 90%. Although a reduction was observed in 2020, coverage levels began to increase again in 2021, with no signs of persistent negative effects.

The COVID-19 pandemic has had a profound and pervasive impact on pediatric vaccination programs globally. As reported by Budhia et al, the health emergency led to a significant contraction in vaccination coverage in many contexts, mainly due to restrictions on mobility, fear of infection, and the necessary reorganization of health services. Our findings are consistent with those reported by Genovese et al (2023), who also observed changes in pediatric vaccination coverage before and during the COVID-19 pandemic in another province of southern Italy. Their results similarly showed that, despite initial declines during the early pandemic phase, coverage levels recovered in the following years, supporting the overall resilience of local vaccination systems [23].

In this complex scenario, the analysis of data from the province of Salerno between 2016 and 2022 offers interesting insights into the capacity of local systems to guarantee continuity and adherence to vaccination calendars, despite widespread criticalities and unprecedented organizational challenges [15]. The observed coverages were compared with the objectives of the National Vaccine Prevention Plan, which provides for 95% or greater for mandatory antigens. Coverage in the province of Salerno is aligned with these targets, suggesting adequate functioning of vaccination services even during the pandemic.

Regarding the hexavalent vaccine (protecting against diphtheria, tetanus, pertussis, poliomyelitis, hepatitis B, and Haemophilus influenzae type b), coverage remained high throughout the entire considered period. In particular, values consistently above 94% were observed in the province of Salerno, with peaks of over 95% in several years (2017, 2018, 2019, and 2022). This trend aligns with that observed in Campania, where coverage consistently exceeded 95% since 2017, and with national data, which indicate slightly lower coverage, albeit still close to this threshold [24]. The analysis by Sabbatucci et al documented a slight decrease in hexavalent coverage in Italy in 2020 compared with 2019 (−0.99%), mainly attributable to the indirect effects of the COVID-19 pandemic. These effects manifested themselves through reduced access to vaccination services and the fear of contracting SARS-CoV-2 infection, dynamics that affected the different regions with varying intensity [22].

In contrast, there was a gradual decline in hexavalent coverage in the autonomous province of Bolzano until 2021 (75.62%), with a slight recovery in 2022 (78.88%) [25]. A steady increase in MMR vaccine coverage was also observed in the province of Salerno from 2016 (87.75%) until 2021 (93.26%), with a slight decrease in 2022 (93.00%) [26].

While these figures are slightly below the regional average for Campania (94.72% in 2021), they are in line with the national trend, where coverage reached 94.4% in 2022. Salerno’s figures are notably higher than those in Sicily (89.20% in 2021) and Alto Adige (71.07% in 2021), indicating strong local adherence to MMR vaccination [24].

Finally, with regard to varicella vaccination, the province of Salerno saw a substantial increase over the years, rising from 67.26% in 2016 to over 90% between 2021 and 2022. This mirrors the regional trend, with Campania initially showing modest values (58.9% in 2017), increasing to over 91% in 2021 and decreasing slightly to 90.48% in 2022 [26]. This upward trend may reflect several contextual factors, including the progressive implementation of Law 119/2017, targeted catch-up programs, digital reminder–recall systems, and post-pandemic reorganization of preventive services within the local health authority.

Nationally, varicella coverage reached 93.35% in 2022, reflecting a similar pattern. Once again, the province of Salerno achieved better results than other regions, such as Sicily (89.20% in 2022) and South Tyrol (76.03%) [24]. Overall, data from the province of Salerno indicate high and increasing adherence to vaccination programs for all vaccinations under study. Compared with regional and national averages, the province performed particularly well in terms of varicella coverage, with stable values close to ministerial targets for MMR and hexavalent vaccines. These results highlight the effectiveness of local strategies to promote vaccination, even in a context characterized by the ongoing pandemic, which led to greater drops in vaccination coverage elsewhere. The differences observed between the province of Salerno and the regional and national data must be interpreted in light of some structural and demographic factors. First, the organization of vaccination services in Campania, characterized by a widespread network of health districts and an early activation of post-pandemic recovery campaigns, could have favored greater resilience compared with that in other regions. Furthermore, the differences in vaccination policies, in the methods of active invitation, and in the adoption of digital reminder-recall systems may have contributed to the regional variations recorded. Local demographic characteristics, such as a younger population and higher population density in some areas, may also have influenced both the demand for services and the ability of districts to maintain high levels of coverage. Finally, regions such as the autonomous province of Bolzano historically present higher levels of vaccination hesitancy and a different socio-cultural structure, which may explain the greater variability in coverage. Considered together, these elements suggest that comparisons between regions should be interpreted not only in quantitative terms, but also within their respective organizational and socio-demographic contexts [27].

From a public health perspective, the findings of this study also suggest broader policy implications. To ensure high and resilient childhood vaccination coverage, particularly during periods of health system stress, such as the COVID-19 pandemic, health authorities should prioritize interoperable immunization registries, robust active recall systems, and strengthened district-level capacity. In addition, formalized catch-up plans to be activated during emergencies, close collaboration with primary care pediatricians, and flexible service delivery models are key components of resilient vaccination strategies. These elements, although not directly analyzed in the present study, are consistent with national and international evidence and may inform future planning in similar contexts.

From a methodological point of view, the use of aggregate data prevents the application of more advanced multivariate models, such as logistic regressions or mixed models, which would have allowed us to control simultaneously for multiple factors. The use of the chi-square test and descriptive analyses, although appropriate for the structure of the available data, does not allow causal relationships to be established. Interrupted time series analysis approaches also have inherent limitations, in particular related to the relatively small number of time points and the possibility of unmeasured confounders in the pandemic period. Despite these limitations, the results obtained offer a robust and coherent picture of the trend of vaccination coverage in the context studied.

Conclusions

The data above reveal a generally positive trend from 2016 to 2021 for coverage against measles, mumps, rubella, and especially varicella, with exceptions during 2020–2021 in Sicily and in 2021 in South Tyrol. Over the same period, coverage for diphtheria, tetanus, pertussis, hepatitis B, Haemophilus influenzae type b, and poliomyelitis remained essentially stable in Campania, Lazio, and nationwide, and decreased slightly in Sicily during 2020–2021; South Tyrol showed a clear negative trend.

The 2022 data show variability for the MMR vaccine: while coverage declined slightly in Campania and Lazio, this was not the case in Italy as a whole, Sicily, or especially South Tyrol. Varicella coverage increased in all areas except Campania, with South Tyrol once again showing the most significant increase. Hexavalent vaccine coverage increased across the board, except in Campania, where it remained stable at a high level.

Comparing the regions studied, Lazio consistently achieved the highest coverage, followed by Campania and Sicily; the autonomous province of Bolzano recorded the lowest figures.

A final consideration concerns the relationship between the data presented and the vaccination coverage target set by the WHO and the National Vaccination Prevention Plan (95%): consistent achievement and surpassing of this threshold were observed only in Lazio and for the hexavalent vaccine in Campania. Nationally, while hexavalent data occasionally exceeded this target, MMR and varicella coverage always remained below it.

The results confirm that pediatric vaccination coverage in the province of Salerno remained high even during the pandemic, highlighting the resilience of the local vaccination system and the organizational capacity to guarantee stable immunization levels even in crisis conditions.