Table 1.

Characteristics of included studies.

Study	Country	Population	Study Period	Study Design	Vaccine/ Disease	Intervention	Outcomes	Results
Cohen R. et al. (2020) [11]	France	1500 mothers of 0 to 17-month-old infants	2017–2019	Survey	Pertussis Hib HepB Measles- mumps- rubella (MMR)	Change from recommended to mandatory vaccination against 8 diseases for all children born from Jan 2018	VC	VC against pertussis and Hib was high and stable in 2019 (≥ 94%) compared to previous years. Among 250 children aged 6 to 8 months old, HepB VC, significantly increased from 88.7% in 2017 to 96.6% in 2019 (P < 0.01). Among 250 children aged 9 to 11-month-old, HepB VC significantly increased from 87.8% to 95.7% between 2017 and 2019 (P < 0.01). Among 250 children aged 15 to 17 months, HepB VC significantly increased between 2017 and 2019 (from 86.1% to 93.0%, P < 0.05). MMR VC increased from 85.5% in 2017 to 89.5% in 2019.
Lévy-Bruhl D. et al. (2019) [12]	France	Children born in 2015–2018 in France	2016–2018	Registry analysis	Hexavalent HepB MMR	Change from recommended to mandatory vaccination against 8 diseases for all children born from Jan 2018	VC	Increase of VC against HepB from around 92% in 2017 to 98% in 2018. The increase in MMR first dose VC between 2017 and 2018 was 3.0%. This compared with a 0.3% gain in coverage between 2016 and 2017. The proportion of children under 1 year old, receiving a hexavalentvaccine increased from 93.1% in 2017 to 98.6% in 2018.
Taine M. et al. (2021) [13]	France	Children ≤24 months old	2019–2020	Registry analysis	Penta/HexavalentMMR	Change from recommended to mandatory vaccination against 8 diseases for all children born from Jan 2018	VC, Vaccine dispensation	During the first 4 weeks of the first lockdown, the observed priming dose counts substantially decreased (RD: from −5.7% (95% CI −6.1; −5.2) for penta/hexavalent to −25.2% (95% CI −25.6; −24.8) for MMR), as did the booster counts (RD:−15.3% (95%CI −15.9; −14.7)) for penta/hexavalent. During 2020, MMR priming doses had the greatest shortfalls (n = 84,893). The number of booster dispensations between March 16 and December 20, 2020 had shortfalls reaching 21,140 doses of penta/hexavalent (RD −4.5% (95% CI −4.8; −4.2)).
Matysiak-Klose D. et al. (2021) [14]	Germany	The population of Germany	2018–2021	Registry analysis	Rubella Measles	The law for protection against measles and to strengthen vaccination prevention in force since 1 March 2020.	Incidence	The number of reported rubella cases had consolidated at a low level in 2018 and 2019 (n = 58). In 2020: 18 rubella cases. In December 2020 Germany was granted an interruption of the endemic transmission for 36 months with retroactive effect for the years 2017 to 2019 and thus, the status of elimination of the rubella. 2018 (n = 545 measles cases) and 2019 (n = 515 measlescases). In 2020, 76 measles cases registered, decrease by 85.5% compared to previous years since 2016.
Neugebauer M. et al. (2020) [15]	Germany	1594 adults	20 October 2019 to 24 April 2020	Survey	Measles	The law for protection against measles and to strengthen vaccination prevention in force since 1 March 2020.	Incidence, VC	19.3% of the participants were affected by the Measles Protection Act. Of these, only 77.5% had an immunity against measles, 14.0% wanted to be fully vaccinated against measles when the measles protection law came into force, whereby an immunity of 91.5% could be achieved. Assuming that participants with an unclear vaccination status or measles disease are immune, an immunity of > 95% is achieved. 86.4% of the children (2–17 years) had immune protection. The willingness of parents to have their children vaccinated because of the sanctions of the Measles Protection Act was only 0.8%.
Robert Koch Institute (2021) [7]	Germany	The population of Germany	2019–2020	Registry analysis	Diphtheria Pertussis HepB Hib Measles Mumps Rubella Varicella	The law for protection against measles and to strengthen vaccination prevention in force since 1 March 2020.	Incidence	Cases n		2019		2020
								Measles		515		75
								Rubella		18		7
								Diphtheria		15		16
								Pertussis		10,315		3451
								HepB		8941		6695
								Hib		955		480
								Mumps		593		338
								Varicella		22,681		11,250
Robert Koch Institute (2021) [16]	Germany	The population of Germany	2020–2021	Registry analysis	Diphtheria Pertussis HepB Hib Measles Mumps Rubella Varicella	The law for protection against Measles and to strengthen vaccination prevention in force since March 1, 2020.	Incidence	Cases n		Jan–May 2020		Jan–May 2021
								Measles		75		4
								Rubella		4		2
								Diphtheria		9		0
								Pertussis		2895		290
								HepB		2942		3061
								Hib		387		77
								Mumps		265		38
								Varicella		7300		2200
Adamo G. et al. (2019) [17]	Italy	The population of Italy	2013–2018	Registry analysis	Measles Rubella	Extension of the number of mandatory vaccinations, for school attendance, from four to ten in July 2017.	Incidence, VC	In 2017, measles incidence increased to 88.4/106 population. In 2018, measles incidence was 43.3 /106 population. Rubella: incidence remained relatively low over the period considered. Congenital rubella syndrome: one case has been reported in Italy since 2014. Vaccination coverage for measles-containing vaccine increased by 5.7 percentage points in 2018 compared to 2016 with regard to the 1st dose (87.3% in 2016 vs 93.0% in 2018) and by 6.6 percentage points with regard to the 2nd dose (82.2% in 2016 vs 88.9% in 2018). Similar trend observed for the first and second doses of rubella-containing vaccine.
Costantino C. et al. (2020) [18]	Italy	Children < 7 years old in Palermo	2016–2018	Registry analysis	Hexavalent Measles-mumps-rubella-varicella (MMRV)	Extension of the number of mandatory vaccinations, for school attendance, from four to ten in July 2017.	VC	Full cycle hexavalent coverage rates showed an increase of 1.4% and 2.5% at 24 and 36 months respectively, from 2016 to 2018. Moreover, in the same period, a 7.2% and a 10.5% increase of adherence to first dose of MMRV were observed at 24 and 36 months, respectively. Vaccination coverage rates for full vaccination cycle of MMRVin the Palermo Local Health Unit, among 6 years old children, showed an increase from 61% to 89.7% (+28.7%) from 2016 to 2018.
Gianfedi V. et. al. (2019) [19]	Italy	Children < 24 months of age	2015–2017	Survey	Measles Polio	Extension of the number of Mandatory vaccinations, for school attendance, from four to ten in July 2017.	VC	Decrease in missed vaccination after the introduction of mandatory law for both polio and measles (−4.1%) with the consequent increase of VC. For measles vaccination the reason “found/contacted, but did not attend the appointment” was the most frequent (mean value 3.2%; 3.7% in 2015, 3.7% in 2016, and 2.3% in 2017), followed by “definitive informed dissent” (mean value 2.9%; 4.0% in 2015, 3.0% in 2016 and 1.8% in 2017).
Gori D. et al. (2020) [20]	Italy	Children < 8 years old in Emilia- Romagna and Sicily regions	2009–2018	Registry analysis	MMR	Extension of the number of Mandatory vaccinations, for school attendance, from four to ten in July 2017.	VC	Observed 4.1% increase in Emilia-Romagna and 6.4% increase in Sicily in VC for MMR in 2017, and an additional 2.5% in Emilia-Romagna and 5.3% in Sicily in 2018. Both regions showed similar results; they achieved the lowest coverage rates in 2015 and showed an increase in the VC after the introduction of mandatory vaccinations. In 2018, both reached the starting point before the decrease.
Signorelli C. et al. (2018) [21]	Italy	The population of Italy	2000–2017	Registry analysis	Polio Tetanus Diphtheria Pertussis HepB Hib Measles Mumps Rubella	Extension of the number of Mandatory vaccinations, for school attendance, from four to ten in July 2017.	VC	VC has increased since 2016 for both mandatory and recommended childhood vaccines. The increase has been consistent—although at different rates—in all regions and is highest for MMR, as compared to other vaccines.
								VC		2016		2017
								Polio		93.3		94.5
								Tetanus		93.7		94.6
								Diphtheria		93.6		94.6
								Pertussis		93.6		94.6
								HepB		93		94.3
								Hib		93.1		94.2
								Measles		87.3		91.7
								Mumps		87.2		91.6
								Rubella		87.2		91.6
Signorelli C. et al. (2019) [22]	Italy	Children ≤ 24 months of age in Italy	2000–2018	Registry analysis	Poliomyelitis MMR	In 2007 Veneto region suspended mandatory immunization against polio, hepatitis B, tetanus, and diphtheria for children. Extension of the number of mandatory vaccinations, for school attendance, from four to ten in July 2017.	VC	Initially no significant drop in coverage rates in Veneto, as compared to previous years. Long-term data show for Veneto Region greater decreases in coverage rates (−5.0% for polio vaccine between 2006 and 2016), as compared to figures reported at the national level (−3.2% for polio vaccine in the same study period) and in other neighboring regions. In 2017 VC against polio was 94.5%, a 1.2% increase compared with 2016 with 11 regions exceeding 95%. MMR coverage was 91.6% for the year 2017, showing a 4.4% increase compared with 2016 (87.2%). The increasing trend in VC has continued in 2018. Data confirm a positive impact of the law on coverage rates which increased for MMR and polio by, respectively, 3.1% and 0.7% after 2017.
Zanella B. et al. (2020) [23]	Italy	Pediatric and adolescent (1–18 years) residents of the province of Florence	December 2017– April 2018	Retrospective	Measles	Since 2017, the anti-measles Vaccination Became Compulsory in minors (0–16 years) for school attendance.	Seropreva-lence	No measles notification was reported. The overall seropositivity was 88.5%, and highest immunity level was found in the 5–9-year-old subjects (97.9%). Comparing these results with two serosurveys carried out in 2003 and 2005–2006, the current study highlighted a dramatic decrease in susceptibility towards measles (8.5%), with a lower value than in 2003 (30.8%) and in 2005–2006 (25.5%). The recent decrease in the susceptibility towards measles in the pediatric and adolescent population of Tuscany, together with the increased measles seroprevalence, is mainly due to all the preventive measures implemented in Italy.
Heininger U. et al. (2016) [24]	Multi-country. Data on Latvia extracted	The population of Latvia	2000–2013	Registry analysis	Pertussis	Adoption in 2000 of “Vaccine Regulation” No. 330 which specifies that vaccination shall be mandatory for children against 10 vaccine-preventable diseases.	Incidence, VC	VC: From 1958 to 2004: 89.7–94.7% From 2005 to 2009: 92.3–98.1% Since 2010: 90.0–97.9% Approximately ten-fold decrease in the reported annual pertussis incidence rate between 2000 and 2011, before a dramatic increase in 2012. Over the period, the annual incidence of reported pertussis cases ranged from 0.4 to 13 cases per 100,000 population.
Kantsone I. et al. (2016) [25]	Latvia	The population of Latvia	1994–2014	Registry analysis	Diphtheria	Adoption in 2000 of “Vaccine Regulation” No. 330 which specifies that vaccination shall be mandatory for children against 10 vaccine-preventable diseases.	Incidence, VC	Increasing incidence observed in 2000 (11.1/100,000). From 2000 to 2014, childhood VC with a third dose ranged from 91% to 98% and with a fifth dose from 92% to 98%. From 2000 to 2014, VC for adolescents (sixth dose at 15 years) ranged from 86% to 96%, decrease in coverage occurred from 96% in 2007 to 86% in 2014. Incidence increased from 0.1 per 100,000 inhabitants in 2010 to 0.7 in 2013. No cases in children were observed from 2009 to 2011, but new cases have emerged since 2012. Most cases occurred in adults.
Wagner K. et al. (2012) [26]	Multi-country. Data on Latvia extracted	The population of Latvia	2000–2009	Registry analysis	Diphtheria	Adoption in 2000 of “Vaccine Regulation” No. 330 which specifies that vaccination shall be mandatory for children against 10 vaccine-preventable diseases.	Incidence, N of deaths	Diphtheria incidence decreased in Latvia from 111.22/million in 2000 to 2.67/million in 2009. During 2000–2009, a total of 32 deaths caused by diphtheria were reported in Latvia. 64 patients in Latvia recorded as fully vaccinated had classic respiratory diphtheria symptoms. Most of these patients were infected during a military outbreak in 2000 and would have been scheduled for primary vaccinations during the 1980s, when changes led to less intensive vaccination of children in the former Soviet Union.
World Health Organization (2020) [27]	Latvia	The population of Latvia	1980–2019	Registry analysis	Diphtheria Tetanus Pertussis (DTP) HepB Hib Measles Mumps Rubella Polio Measles- containing vaccine (MCV)	Adoption in 2000 of “Vaccine Regulation” No. 330 which specifies that vaccination shall be mandatory for children against 10 vaccine-preventable diseases.	VC, incidence	VC	2002	2001	2000	1999	1998
								DTP1	99	100	100	93	99
								DTP3	97	97	96	95	94
								HepB3	98	96	95	94	9
								Hib3	87	84	79	76	47
								MCV1	98	98	97	97	97
								Pol3	98	97	96	95	94
								Cases n
								Diphtheria	45	91	264	81	67
								Measles	-	1	0	0	3
								Mumps	231	6834	1949	41	-
								Pertussis	159	160	135	55	149
								Rubella	2578	358	62	91	-
								Tetanus	1	2	3		1
Bukova V. et al. (2017) [28]	Moldova	The population of Moldova	1993–2016	Registry analysis	Pertussis	From 2009 children are required to receive all vaccines in the national schedule to enroll in kindergartens and schools.	Incidence, VC	Reduction of incidence in 2009–2010 from 48 to 31 cases with increase in incidence in the following years. In 2009–2013 vaccination coverage was above 90%, and under 90% in the following years. The lowest incidence for the analyzed years was observed in 2005–2010—within 24 to 48 cases annually. Progressive reduction of the vaccine coverage observed in 2008–2015, from 95.4 to 89.7%, caused an increase in the incidence.
Melnik A. et al. (2019) [29]	Moldova	The population of Moldova	2000–2018	Registry analysis	Measles	From 2009 children are required to receive all vaccines in the national schedule to enroll in kindergartens and schools.	Incidence, VC	In 2003–2017, the incidence dropped sharply, with a total of 181 cases of measles reported. No measles cases were reported in 2008–2011 and in 2015–2017. MMR1 VC: gradual decrease in 2003–2017, the lowest rate is observed in 2017—87.1%. In 2009–2012 VC was stable at the level of 90%. Moldova achieved the status of a country that eliminated measles in 2008–2017. Among the cases, children from one to ten years predominate (66.1%), cases among children under one year old (8.2%), adolescents (17.5%) and adults (8.2%).
World Health Organization (2020) [27]	Moldova	The population of Moldova	1980–2019	Registry analysis	Diphtheria Tetanus Pertussis HepB Hib Measles Mumps Rubella Polio	From 2009 children are required to receive all vaccines in the national schedule to enroll in kindergartens and schools.	VC, incidence	VC	2011	2010	2009	2008	2007
								DTP1	96	93	95	96	95
								DTP3	93	90	94	90	92
								HepB3	96	98	95	97	95
								Hib3	78	63	94	-	-
								MCV1	91	97	91	95	96
								MVC2	97	98	98	97	95
								Pol3	96	97	95	96	93
								Cases n
								Diphtheria	0	0	1	0	0
								Measles	0	0	0	0	10
								Mumps	143	144	292	29783	1757
								Pertussis	102	31	47	30	36
								Rubella	0	0	1	1	3
								Tetanus	0	2	0	0	0
Patić A. et al. (2020) [30]	Serbia	3404 participants from Vojvodina Province aged 0–84	May 2015– December 2017	Retrospective	Rubella	At the beginning of 2016, the National Assembly adopted a Law on Protection of the Population from Infectious Diseases, mandating vaccination.	Incidence, seroprevalence, VC	From 2008 to 2017, only three cases of rubella were reported (in 2009, in 2012, and in 2015). The highest number of seronegatives was in the youngest (1 year) age group (44.7%), followed by the group aged 24–49 (6.4%) and 2–11 years (6.2%). In the group of children aged 2–11 years, the level of anti-rubella IgG antibodies was higher since any of them have received both doses of the MMR vaccine. VC in Vojvodina was lower than 95% in 2012 (91%), 2014 (86%), 2015 (90%), 2016 (89%), and 2017 (78%). Coverage with the second dose of MMR increased significantly since 2015: 2015 (83,7%), 2016 (90,9%), 2017 (93,2%).
Ristić M et al.(2019) [31]	Serbia	3199 residents of Vojvodina province aged 12 months and older	April 2015–June 2017	Retrospective	Measles	At the beginning of 2016, the National Assembly adopted a Law on Protection of the Population from Infectious Diseases, mandating vaccination.	Incidence, seroprevalence, VC	Declining trend of measles incidence in Vojvodina in 1948–2017 was observed with wide variation in annual notification rates from 768.8/100,000 in 1970 to 0 during 12 different periods/years (2001–2006, 2008–2011, 2012, and 2016). VC for both MMR1 and MMR2 vaccines in Vojvodina increased from 78% and 93% (at the end of 2017) to 90% and 94% (during the first two months of 2018), respectively. Findings showed that the main susceptible age group for measles transmission in the province are the subjects aged 20–39 years.
World Health Organization (2020) [27]	Serbia	The population of Serbia	1980–2019	Registry analysis	Diphtheria Tetanus Pertussis HepB Hib Measles Mumps Rubella Polio	At the beginning of 2016, the National Assembly adopted a Law on Protection of the Population from Infectious Diseases, mandating vaccination.	VC, incidence	VC	2019	2018	2017	2016	2015
								DTP3	97	97	95	93	95
								HepB3	94	91	93	91	94
								Hib3	97	97	95	92	95
								MCV1	87	93	86	82	87
								MVC2	91	90	91	90	87
								Pol3	97	97	95	93	95
								Cases n
								Measles	22	5076	721	11	383
								Mumps	-	13	37	40	41
								Pertussis	-	351	285	148	89
								Rubella	-	5	5	5	10
								Tetanus	-	0	2	4	4
Public Health Center of the Ministry of Health of Ukraine (2021) [32]	Ukraine	The population of Ukraine	2017–2020	Registry analysis	Polio DTP HepB Hib MMR	From 2019, unvaccinated children are prohibited from attending educational institutions.	VC	VC			2020	2019	2018
								DTP			80.1	80.5	69
								HepB			96.5	76	67
								Hib			83.6	80	58
								MMR1			83.3	93.2	91
								Polio			83	78.4	71
Public Health Center of the Ministry of Health of Ukraine (2021) [8]	Ukraine	The population of Ukraine	2018–2021	Registry analysis	Tetanus Diphtheria Pertussis Hepatitis B Hib Measles Mumps Rubella	From 2019, unvaccinated children are prohibited from attending educational institutions.	Incidence	Cases/100,000			2020	2019	2018
								Measles			0.63	135	125
								Mumps			0.39	0.90	0.92
								Pertussis			2.48	5.48	5.22
								Rubella			0.09	0.33	0.55
								HepB			1.74	3.11	3.42
								Cases n
								Tetanus			12	15	18
								Diphtheria			0	21	10
								Hib			10	25	75