INTRODUCTION

Vaccines are biological results that encompass one or multiple antigens that are supplied with the purpose of performing a respective immune stimulus, which seeks to mimic the natural infection, developing immune replication with the purpose of safeguarding it in the following presentations to the respective microorganism.¹They constitute one of the most efficient public health interventions in terms of cost reduction and morbimortality of preventable infectious and contagious diseases.²Systematic vaccination programs have led to the disappearance of smallpox, reduction of the spread of poliomyelitis in practically the whole world and the surveillance of diseases such as measles, tetanus, diphtheria, rubella or massive Haemophilus influenzae disease.¹

The World Health Organization indicates that organized vaccination covers four out of five children where all three doses of diphtheria, tetanus and pertussis vaccine (DTP3) have been administered, in order to safeguard them against dangerous infectious diseases that can lead to severe disorders and disabilities up to mortality.³

A nivel mundial según la OMS, la cobertura de inmunización sigue siendo desde 2010 alrededor del 86%. Se necesita una cobertura del 95% a escala mundial que abarque a los países y las comunidades para garantizar la protección contra los brotes de enfermedades que pueden prevenirse con vacunas.⁴

Globally according to WHO, immunization coverage remains around 86% since 2010. A 95% coverage is needed globally covering countries and communities to ensure protection against vaccine-preventable disease outbreaks.⁴

In Peru, there is a national vaccination scheme which has a succession of the organization and the way vaccines are provided formally accepted by the Ministry of Health with the purpose of cooperating to increase the quality of health of the inhabitants by controlling preventable immune diseases being seventeen vaccines incorporated in the national scheme up to the year of age.⁴There are vaccination indicators that allow monitoring the access, follow-up, results and impact of "The National Sanitary Strategy of immunizations" where the percentages that measure the performance and coverage for the fulfillment of the complete vaccination in a child are calculated.⁴

In Peru, vaccination percentages are obtained through the Demographic and Family Health Survey (ENDES).⁴Therefore, it is of vital importance to determine the main risk factors in our environment that generate non-compliance with the basic vaccination schedule and thus detect them in order to generate recommendations for adequate compliance and expand national coverage.⁵

METHODOLOGY

RESULTS

Of the 18,104 children, it was found that 10,044 children did not comply with the basic vaccination schedule, 55.5% of the total. (Figure 1)

Figura 1.  Children over 12 months older according to compliance with the vaccination scheme - BCG 1, HVB, Penta 1, Polio 1, Rota 1, Neumo 1, Penta 2, Polio 2, Rota 2, Neumo 2, Penta 3, Polio 3, SPR1, Neumo 3 e Influenza. 

In the same work with the total sample of 18 104 another analysis was performed taking to the vaccination scheme to 7 main vaccines according to previous studies; BCG, DPT1, POLIO 1, DPT2, POLIO 2, DPT3 AND POLIO 3 where it was found that 3 863 minors failed to comply with the vaccination scheme being 21.3% of the total.

Regarding the general characteristics of the mothers in this sample, it was observed that 70% belonged to urban areas and 30% to rural areas, 4.3% were between 12 and 19 years old, 65.5% were between 20 and 34 years old and 30.2% were between 35 and 49 years old. In the highest level of education 1.6% had no education at all, 20.1% had primary education, 44.7% had secondary education and 33.6% had higher education. In the level of wealth 28.4% were very poor, 26.2% poor, 19.6% medium, 14.8% rich and 10.9% very rich. According to natural region 12.4% lived in metropolitan Lima, 29.6% in the rest of the coast, 34% in the highlands and 24% in the jungle. According to prenatal checkups 89.3% had more than 6 NPC and 10.7% between 1 and 5 NPC and according to the application of tetanus vaccine 76.7% received and 23.3% did not receive it. (Table 1)

Regarding the risk factors according to non-compliance with vaccination, the p-value of area of residence 0.004, age 0.000, maximum level of education 0.345, wealth index 0.000, natural region 0.000, prenatal controls 0.000 and tetanus vaccination in pregnancy 0.000 were found. (Table 2).

DISCUSSION

Non-compliance with the vaccination schedule goes hand in hand with the health of the child, which is why it is a global public health strategy since it prevents mortality in children; according to the WHO³, compliance with the vaccination schedule is 90% worldwide.

Vaccination non-compliance rates vary according to the income of the countries, with middle and low income countries having a high rate on average and higher income countries having a lower rate. The rate in China, according to Cao et al⁶, reports 6.9% non-compliance in younger children. On the other hand, in Mexico, a country with similar sociocultural and demographic characteristics to our country, Palacios⁷estimated the rate of noncompliance with the vaccination schedule in younger children at 35%.

In our study, 55.5% of children between 1 and 5 years of age did not comply with the vaccination schedule, a rate above that of middle and high income countries and far from the WHO world recommendations. Similarly, in the Peruvian population, Achuquín⁸in 2017, found 22% non-compliance with the scheme, so we deduce that the percentage found in our study would not be in the expected range since the previous study did not take into account the complete scheme but only 7 main vaccines and in an analysis where the same vaccines were taken, it was found that 21.3% of children aged 1 to 5 years did not comply with the vaccination scheme in 2018 according to ENDES, which would be in the expected range according to INEI.⁹

Maternal age is related as risk behavior and with greater difficulty in making decisions, probably due to hormonal changes and this development is not synchronous between the prefrontal area with respect to those related to socioemotional processes⁸. Sheikh et al¹⁰in Bangladesh, found that a maternal age younger than 20 years was related to noncompliance (OR= 3.21, p < 0.05, CI= 1.02- 10.13). Likewise Ali¹¹in 2017 showed an association between mothers between 19 to 26 and noncompliance with the scheme (OR = 9.59) and Cabrejos¹²in 2017 in his study conducted in Peru, found maternal age as a factor associated with noncompliance with the scheme. Similarly, in our study it was found that maternal age between 12 and 19 years was associated 1.20 times higher than between 20 and 34 years of age of the mothers, increasing the risk of noncompliance with the vaccination schedule. Thus, maternal age was found to be a factor associated with noncompliance with the vaccination schedule.

Adequate prenatal follow-up is associated with a lower number of obstetric complications and with making the mother aware of the care and pertinent behaviors to follow during pregnancy, the main ones being compliance with immunizations and prenatal controls.^8,13In Peru, according to MINSA, prenatal controls must be at least 6 CPN to be considered adequate follow-up and to guarantee the wellbeing of the baby, if there are fewer or no prenatal controls, this can generate a high risk for the mother and the baby, which often affects development⁸. In the study, non-compliance with the vaccination schedule was found to be 1.28 times higher in pregnant women with less than 6 prenatal checkups than in pregnant women with 6 or more prenatal checkups. Likewise, Ali¹¹in 2017 found an association between fewer prenatal checkups and noncompliance with the vaccination schedule (OR = 9.59), Nozaki¹³found that having more than 4 checkups was associated with compliance with the vaccination schedule (OR: 1.87, 95% CI: 1.28- 2.73) and Achuquín⁸in 2017 in Peru (OR= 2.19, p=<0.01, CI= 1.79- 2.51) found that prenatal checkups are a factor associated with noncompliance with the vaccination schedule.

The application of the tetanus vaccine during pregnancy serves to guarantee the wellbeing of the baby during gestation, since if it is not applied it can generate risk for the baby, which often affects its development.^8,13The study found that not applying the tetanus vaccine was associated 1.28 times more than in children of mothers with tetanus vaccine application, increasing the risk of non-compliance with the vaccination schedule. Similarly Ali¹¹in 2017 found an association between tetanus vaccination and compliance with the vaccination schedule (OR = 9.59). A similar finding was that of Nozaki¹³found an association between the application of tetanus vaccine during gestation and compliance with the vaccination schedule (OR: 1.87, 95% CI: 1.28- 2.73) and Achuquín⁸in 2017 in Peru obtained that not having received the tetanus vaccine (OR= 2.19, p=<0.01, CI= 1.79- 2.51). The application of vaccines in pregnant women generates awareness and adherence to the vaccination schedule in their children; therefore, not applying the vaccine is a risk factor.

The area of residence, in rural areas is related to the poor accessibility of vaccines associated with non-compliance with the vaccination schedule¹⁵. As well as 2017 in Colombia, Salas¹⁴obtained 26% in rural areas and Achuquín⁸in Peru found 23.6% in rural areas (p <0.01, OR= 0.97, CI= 0.84 - 1.12) related to non-compliance with the vaccination scheme in minors. On the other hand, Garcia¹⁵in Apurimac-Peru in 2015 obtained 36.7% of children in rural areas did not comply with the vaccination schedule. In our study, it was found that 24% of children under 5 years of age did not comply with the vaccination schedule and live in rural areas; statistical significance was not found in accordance with the background.

According to the maximum level of education of the mother, incomplete or deficient training can lead to poor knowledge in basic health issues and assimilation of misconceptions causing poor judgment in mothers or caregivers which can generate non-compliance with immunizations for example, adverse reactions can generate lethality, vaccines are not necessary for the development of a child and vaccine myths^8,16. Forshaw et al. in 2017 found that 35% of mothers with primary education did not comply with the vaccination schedule for their children. Similarly, Salas¹⁴in Colombia in 2016 found that 40% of mothers with primary education at the highest level did not comply with the vaccination schedule. On the other hand, in Peru in 2017, Aguilar et al¹⁷obtained 50.1% of mothers with primary education did not comply with the vaccination schedule in their children and Achuquín⁸in the same year obtained 28.2% of mothers with primary or no academic degree did not comply with the vaccination schedule (p= 0.24, OR=1.07, CI 0.95 - 1.21). In our study, 18.5% of mothers with primary education did not comply with the vaccination schedule in their children, in which no statistical association was found according to our antecedents, perhaps due to the association of the variables and the sample.

The wealth index could have an association because, although vaccines are free, the condition of poverty means that mothers are often unable to take their children to the health center because they do not have the economic means such as transportation and food, among others⁸. Morton⁽¹¹⁾in Australia in 2018 found that 26% of children in extreme poverty did not comply with the vaccination schedule and Sheikh et al⁽¹⁰⁾in Bangladesh identified extreme poverty as a risk factor associated with non-compliance with vaccination with an OR= 2.2. Likewise, Achuquín⁽⁸⁾in Peru found 28.2% poverty (OR= 1.10, p= <0.01, CI= 1.07- 1.26) found socioeconomic status as a factor associated with noncompliance (gamma= 0.553, sig (Bilateral)= 0.003 and p= 0.01). In our study we found that 24.4% of children in the very poor quintile did not comply with the vaccination schedule, but without statistical association, in contrast to our antecedents, because the antecedents that did show an association were in other countries or with samples of minors.

According to the natural region considering the accessibility of vaccines, being better in lima because in provinces there is difficulty in transporting and complying with the entire cold chain in vaccines⁽¹⁶⁾. According to Achuquín⁸in 2017, there was no association between the natural region and non-compliance with vaccination.

As in our study, it was found that 26.1% of underage children did not comply with the vaccination schedule in the highlands. In both studies, no statistical association was found, which could be due to the sample and size.

CONCLUSIONS

• Through our work, it was obtained that the variable young age of the mother, prenatal controls less than 6 and the non-application of tetanus vaccine in the pregnant woman is associated as a risk factor for noncompliance with the vaccination schedule in children under 5 years of age in 2018.

• No significant association was found between noncompliance with the vaccination schedule in children under 5 years of age with the place of residence, educational level of the mother, wealth index and natural region possibly due to the population used, as this generates many biases and limits the study.