ABSTRACT
Children living with Human Immunodeficiency virus (HIV; CLH) have special vaccine needs. Determinants of household-level uptake of vaccines need to be examined in high-risk families with CLH. We previously conducted a study on the impact of Haemophilus influenzae type b conjugate vaccine and pneumococcal conjugate vaccine (PCV-13) in 125 HIV-affected families and 47 HIV-unaffected families in West Bengal. We then interviewed 99 of these 172 families who had participated in the study to understand the household-level factors that determine vaccine uptake. Sixty-four of the 99 families had one or more CLH. Within these 64 families, 30% of CLH had missed vaccines under the universal immunization program (UIP), compared to only 6% of HIV-uninfected children (HUC) (p = .001). Maternal HIV positivity in a family increased risk of missing UIP vaccines nearly five times (4.82, p = .001). Almost all families accessed UIP vaccines at local primary vaccination centers, but 14% of families experienced stigma due to HIV and avoided getting one or more vaccine doses. In contrast, in our study, 100% of HIV-affected families actively sought PCV-13 and HibCV, despite having to travel. Factors that influenced uptake included awareness generation and activation by an outreach worker and availability of vaccines on pick-up days for anti-retroviral therapy. Eighty-six percent of families strongly recommended PCV-13 to other families. To conclude, while we found that CLH have barriers to getting vaccinations, a program designed to take into consideration the obstacles that HIV-affected families face showed a high rate of vaccine uptake.
Children living with HIV (CLH) and HIV-exposed uninfected children (HEU) are both at increased risk of disease from vaccine-preventable infections. They have special vaccine needs that need to be addressed in vaccination programs.
Although CLH regularly utilizes healthcare services, several studies from sub-Saharan Africa and India, have shown that CLH are at increased risk of missed or incomplete vaccinations compared to HIV-unexposed uninfected children (HUC).Citation1–4 Maternal HIV infection in a family increases the risk for under-vaccination in both CLH and HEU children. Barriers to vaccinations in these high-risk families need to be identified, especially with the adoption of the Immunization 2030 program, which aims for a world where “everyone, everywhere, at every age, fully benefits from vaccines for good health and wellbeing.”Citation5
Acceptance of vaccination at the household-level is an important determinant of vaccine uptake. The determinants of vaccine acceptance include not only perception of the risk of vaccine-preventable disease versus potential adverse effects of the vaccine, but also trust in health systems, cost of vaccines, and sociocultural, historical, and political factors.Citation6 Vaccine hesitancy, which is defined as delay or refusal of vaccination by families despite availability, remains a major barrier in many countries for complete childhood vaccination.Citation7 Thomson identified five causes of suboptimal vaccination, which fall into the categories of access, affordability, awareness, acceptance, and activation, referred to as the “5A practical taxonomy on determinants of vaccine uptake.”Citation8 This taxonomy provides a framework to discuss and improve vaccine uptake with families.Citation9,Citation10
Not much is known about the perception of vaccines, especially acceptability of new vaccines in families affected by HIV in India. With the largest burden of pediatric HIV outside of sub-Saharan Africa, India has rapidly scaled up antiretroviral therapy (ART) services and programs for the prevention of parent-to-child transmissions of HIV. As a result, there is a growing population of HEU children in India. Vaccines are not part of government programs for CLH, HEU children, or adults with HIV.
India has recently introduced new vaccines in the Universal Immunization Program (UIP) that are particularly important for CLH and HEU children: the pentavalent vaccine which includes diphtheria, tetanus, pertussis, Hepatitis B, and Haemophilus influenzae type b (HibCV);Citation11 rotavirus vaccine;Citation12 the pneumococcal conjugate vaccine (PCV13);Citation13 and the measles/rubella vaccine.Citation14 There is as yet no specific schedule for CLH or HEU children and no catch-up schedule for children who are still at risk because of HIV but have aged out of the standard vaccination schedule.
In order to determine barriers to routine vaccinations and determinants of household-level uptake for new vaccines in families affected by HIV, we conducted a household-based study in a cohort of HIV-affected and -unaffected families in West Bengal. We used the 5A taxonomy to understand the most important determinants of vaccine uptake for these families.
From February 2012 to October 2014, 172 families participated in a prospective cohort study looking at the impact of the monovalent Haemophilus influenza type b conjugate vaccine (HibCV, Serum Institute of India), and 13-valent pneumococcal conjugate vaccine (PCV-13, Pfizer), on nasopharyngeal carriage in vaccinated children and their unvaccinated parents in two districts of West Bengal.Citation15–18 The study included 125 HIV-affected children (2–14 years old) who represented nearly all families with CLH at the ART Center of the Midnapore Medical College, and a group of 47 HIV-unaffected families with children between ages 2–5 years. This 2–5 year unaffected group was age-matched with the children 2–5 years in the cohort with HIV. The original sample size was calculated to look at the impact of HibCV on nasopharyngeal carriage in vaccinated children. Children with no history of HibCV and PCV vaccination were eligible for the study and details have been published.Citation18 We systematically collected information on participation in the Universal Immunization Program in all 172 families in one-to-one interviews.
From December 2015 to February 2016, we invited all 172 families to participate in an in-depth interview on drivers of vaccine uptake. 99 families agreed to participate, 64 were HIV-affected, and 35 were not. A social worker conducted the interviews with one parent or guardian, face-to-face in Bengali for 30 minutes, at the ART center in Midnapore Medical College for HIV-affected families, and at the Hijli Rural Hospital-Kharagpur for HIV-unaffected families. The majority of interviews were with mothers (HIV-affected 64%; HIV-unaffected 88%). Interview responses were fully transcribed, translated into English, and entered into Epi-Info 7 (CDC, Atlanta).
Ethical clearance was obtained from the Ethics Committees of all participating institutions. Written informed consent was obtained from parents and guardians.
In HIV-affected families, children and parents had HIV. In the original pneumonia prevention study, prior to study enrollment, group discussions about pneumonia and pneumonia preventing vaccines were held at the antiretroviral treatment (ART) clinic, and in a community center run by a local NGO, working with HIV-affected families. A movie in Bengali featuring a familiar pediatric HIV physician explained the need for vaccines. An outreach worker from the HIV community worked as a resource person for HIV-affected families. The Hib and PCV-13 vaccinations were organized at the ART clinic for CLH on days when they would come for CD4 count checks and medicine pick-up. Families were compensated for travel.
In the HIV-negative cohort, the study was discussed with families at the primary health center (PHC) in the presence of auxiliary nurse midwives (ANM), Accredited Social Health Activist (ASHA) workers, and the Block Medical Officer of Health. The vaccines were given at the PHC where families regularly accessed UIP services.
To assess the determinants of vaccine uptake, we developed a survey, in Bengali, consisting of both multiple-choice questions with a visual analog scale to accommodate literacy levels and open-ended questions. The survey instrument was designed in an iterative manner by a team consisting of physicians, a psychologist, and a social worker. It was then pilot tested in the clinic and reformulated.
Questions on the survey included:
1. Was information about UIP given at the health center prior to vaccination?
2. Are your child’s UIP vaccinations completed?
3. Did you miss or delay any UIP vaccines?
4. Did any geographical factors prevent you from getting UIP vaccines?
5. Were there any past events that discouraged you from getting UIP vaccines?
These and other survey questions were developed with the 5A framework in mind:
1. Access is the ability of individuals to reach vaccines. The survey asked questions about (a) location, (b) time to reach clinic, and (c) availability of vaccine cards.
2. Affordability is the ability to afford vaccination. Participants were asked about (a) travel expenses, (b) willingness-to-pay for Hib/PCV, and (c) the amount they could pay out-of-pocket. A payment card method was used to evaluate the maximum amount of parents would be willing-to-pay.Citation19
3. Awareness is defined as individuals’ knowledge of vaccines and their objective benefits and risks. Questions were asked to determine (a) parental knowledge of pneumonia and (b) what was most important for deciding participation?
4. Acceptance is the degree to which individuals accept, question, or refuse vaccines. Questions to gauge acceptance included:
How likely will you consider Hib/PCV vaccination for your other child?
How likely will you recommend Hib/PCV vaccine to friends and relatives?
How strongly do you feel Hib/PCV has impacted your child’s health?
5. Activation is the nudge toward vaccine uptake. Questions to assess activation were:
How did you come to know about this study?
How difficult was it to decide to participate?
Was the audiovisual discussion understandable?
Did you have an opportunity to ask questions?
Outcome measures were vaccination status of children as per the Expanded Program on Immunization (EPI) recommendations.Citation20 Complete vaccination status was defined as children receiving one dose of Bacillus Calmette–Guérin, BCG vaccine (birth); three doses of oral polio vaccine, OPV (6, 10, 14 weeks); three doses of diphtheria, pertussis, and tetanus vaccine, DPT (6, 10, 14 weeks); and one dose of measles vaccine (9–12 months) by 12 months of age. Incomplete immunization was defined as children who received at least one but not all recommended vaccines by 12 months of age. Un-immunization was defined as children who did not receive any recommended vaccines by 12 months of age. Individual and socio-economic factors that often present barriers to vaccination coverage were chosen as variables for analysis. These included HIV status of child and mother, geography, gender, religion, single-parent household, more than one child in a family, maternal age and education, socioeconomic status, and absence of vaccination card.Citation9,Citation21–23
Data were analyzed using STATA 13 (Stata Corp). Descriptive statistics were calculated and comparisons were made using chi-square or Fisher’s exact test for categorical data, and rank-sum test for continuous data. The risk factors for incomplete or un-immunization were determined by relative risk estimation.
The demographics of the 172 families that participated in the vaccination study are shown in . Ninety-four percent lived in rural households. Sixty-one percent of CLH, and 47% of HUC were male. More HIV-affected households were single-parent households; 37% of fathers and 7% of mothers had died in the HIV-affected group. Both parents were alive in all HIV-unaffected households. The median family income in the groups was INR 9478/month. Ninety percent of HIV-affected and 96% of HUC were Hindus, 10% of HIV-affected, and 2% of HIV-unaffected followed Islam.
Table 1. Demographics and family organization of families who participated in the immunization study (N = 172)
Nearly 95% of CLH and 100% of HUC depended on government programs for routine vaccination. Twenty-two percent of CLH had no vaccination card, while all HUC had cards. It took a median of 4 hours for HIV-affected families to travel the 65 km to the ART center.
UIP vaccination coverage is described in . Out of 172 children, 30% of CLH missed UIP vaccines. Of these 14% of CLH were incompletely immunized and 16% were un-immunized, while all HUC were up-to-date (p = .001). This included 83% BCG, 77% OPV (1–3), 80% DPT (1–3), and 77% Measles-1 coverage in CLH. CLH also missed booster vaccines (only 9% got OPV-4, 14% DPT-4, and <1% got two doses of measles). In HUC 79% got OPV-4, 87% DPT-4, and 2.5% Measles-2 (p < .001 each). Only 35% of CLH ages of 2–5 had 3 doses of Hepatitis B vaccine compared to 85% in the 2–5 year HUC cohort. In the whole cohort of CLH from 2 to 14 years, 27/125 (22%) had gotten three doses of Hepatitis B.
Table 2. Immunization coverage in children living with and without HIV
Barriers to coverage in the universal immunization program were investigated (). Loss of vaccination card in CLH strongly increased their risk of missing UIP vaccines (Risk ratio RR 5.4; 3.4–8.69; p < .001). Maternal HIV (RR 4.8, 1.5–14.9; p = .001) and HIV infection status of child (RR 4.6; 95% CI 1.5–14.3; p = .0013) were major risk factors for incomplete immunizations. Muslims had 2 times increased risk of missing the UIP vaccines (RR 2.15; 1.1–4.6; p = .042). Families where the mother had not been to school had nearly two times increased risk of incomplete child immunization (RR 1.8; p = .042).
Table 3. Factors influencing the risk for incomplete or un-immunization in study children (n = 172)
Open-ended questions on the survey revealed further reasons for missing vaccines that fit within the 5A framework. One mother from the HIV-affected group reported that “after finding out that my child has HIV, I was busy seeing the doctor so I couldn’t take the child for vaccination services.” This suggests she couldn’t afford it due to time constraints, and though she was regularly accessing care, vaccines were not available. Another mother stated that the distance (access) to the vaccination center prevented her from getting vaccines. Nearly 14% (9/64) of HIV-affected families encountered unpleasant experiences at their local UIP vaccination centers, which discouraged them from getting vaccines. All these incidents were of vaccine refusal by a health-care worker after HIV-positive status or thalassemia was detected. Three respondents from the Muslim community reported not having any knowledge or awareness of the vaccines and said religious beliefs prevented them from getting immunized.
In contrast to UIP vaccines, 100% of HIV-affected families actively sought the study vaccines. Awareness generation and activation by the outreach worker from the HIV community was cited as critical by 81% (52/64) of families affected by HIV. For each clinic, families were contacted by the outreach worker by phone or in person, providing a regular nudge. In further discussions of what promoted families to participate, 83% of HIV-unaffected families said activation by PHC staff was key. Thirty-two percent (32/99) felt the audiovisual discussions were essential in deciding to participate. 60% of families said they felt that the vaccines would keep their child healthy, and HIV-affected families cited the availability of vaccines on days of routine ART pick-up as key. Ninety-six percent of families were happy with the quality of service.
Out of 99 respondents, 89% (88/99) were strongly willing to recommend PCV and HibCV to others (). 90% of families considered pneumonia as an important childhood problem, and 69% felt that the vaccines had strongly impacted their child’s health. Despite being aware that 2–3 doses may be needed, 87% (88/99) were willing-to-pay for PCV if not available through the government. The median amount of families were willing-to-pay for three doses of PCV was INR 750 (IQR 500–1500).
Table 4. Responses of HIV-affected families and HIV-unaffected families on the reasons for uptake of study vaccines (HibCV and PCV13)
In summary, we looked at household-level determinants for uptake of new vaccines in high-risk families affected by HIV in West Bengal and the barriers to uptake of UIP vaccines. We found that maternal HIV infection, HIV infection in the child, maternal education, Muslim religion, were all associated with increased risk for a child being incompletely immunized or unimmunized, with UIP vaccines. Interestingly, all families regardless of maternal HIV status, child HIV status, religion, or their previous experience with UIP vaccines, actively sought the HibCV and PCV vaccines.
Again, interpreting the data through the 5A framework, we found high levels of acceptance for HibCV and PCVs; the majority of families would recommend these vaccines to friends and families. Effort was made to engage and communicate with families about the role of vaccines. The outreach worker from the community was instrumental in raising awareness and activating families. Families could access vaccines at a place and time where children routinely got follow-up. By making the vaccines free and compensating travel, vaccine access was made affordable.
A systematic review of reasons for under immunization in low- and middle-income countries cite deficits in vaccination systems, family characteristics, parental attitudes, and problems with vaccination-related communication, as drivers of under immunization.Citation24 Sub-optimal coverage of vaccination in the CLH is a problem in health systems around the world, even though CLH regularly access health care.Citation1,Citation2,Citation25–27
Discrimination due to HIV and negative experiences with the health system are barriers for accessing health services, specifically routine vaccinations, for CLH.Citation24,Citation28,Citation29 Interestingly, introduction of high-quality comprehensive HIV care has been shown to rapidly reduce stigma and increase uptake of HIV services.Citation30 Comprehensive HIV care for children includes vaccines.
We found that families with HIV valued vaccines and were willing-to-pay for three doses of PCV out-of-pocket. The amount they would pay represents nearly 19% of their monthly income.
The study was conducted more than four years ago, but is relevant because there is still no catch-up schedule or specific vaccine schedule for adults or children affected by HIV available in government programs, and no vaccination schedule for revaccination after immune reconstitution. The Indian Academy of Pediatrics recommends vaccinations for CLH following well-articulated international norms.Citation31,Citation32
Hepatitis B and HibCV vaccines are now in India’s UIP, and PCV is being rolled out. Therefore, there is a need for a dedicated vaccination program with a catch-up schedule for CLH.Citation33 Hepatitis B was introduced into the UIP in 2011 and we found large numbers of CLH remained unimmunized because it is not available in HIV programs. Similarly, most CLH did not get two doses of measles vaccine. Comprehensive, high-quality HIV care requires integrating vaccination services for CLH as part of routine HIV care with community engagement, recognizing that these children have special vaccine needs.Citation34
The study has limitations. The study was conducted in a limited number of families with more CLH than HUC. We had no HEU children, and the study was conducted more than four years ago. In this interval, however not much has been published about vaccine acceptance in high-risk families from India. Larger population-based studies are required to validate our cohort findings.Citation19
In conclusion, we found that while CLH had increased risk of missing routine UIP vaccines, families affected by HIV actively sought the HibCV and PCV-13 vaccines due to the system in which awareness was generated, and vaccinations were made accessible and affordable. With improvement in HIV treatment services in India, developing a comprehensive program for inclusion of vaccination services for children and adults affected by HIV in government HIV programs is possible and required, especially now with the adoption of Immunization 2030 seeking to make the full benefits of vaccines available to everybody everywhere.
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References
- Setse RW, Cutts F, Monze M, Ryon JJ, Quinn TC, Griffin DE, Moss WJ. HIV-1 infection as a risk factor for incomplete childhood immunization in Zambia. J Trop Pediatr. 2006;52(5):324–28. doi:10.1093/tropej/fmk002.
- Tchidjou HK, Vescio MF, Sanou Sobze M, Souleyman A, Stefanelli P, Mbabia A, Moussa I, Gentile B, Colizzi V, Rezza G. Low vaccine coverage among children born to HIV infected women in Niamey, Niger. Hum Vaccin Immunother. 2016;12(2):540–44. doi:10.1080/21645515.2015.1069451.
- Adetokunboh OO, Uthman OA, Wiysonge CS. Effect of maternal HIV status on vaccination coverage among sub-Saharan African children: A socio-ecological analysis. Hum Vaccin Immunother. 2018;14:2373–81. doi:10.1080/21645515.2018.1467204.
- Bhattacharya SD, Bhattacharyya S, Chatterjee D, Niyogi SK, Chauhan N, Sudar A. Risk factors for incomplete immunization in children with HIV infection. Indian J Pediatr. 2014;81(9):850–55. doi:10.1007/s12098-013-1049-0.
- WHO. Immunization agenda 2030: A global strategy to leave no one behind. Immun Vacc Biol. 2020. [accessed 2020 April 2]. https://www.who.int/publications/m/item/immunisation-agenda-2030-a-global-strategy-to-leave-no-one-behind
- WHO. What influences vaccine acceptance: A model of determinants of vaccine hesitancy SAGE Vaccine Hesitancy Working Group 2013.
- WHO. Report of the SAGE working group on vaccine hesitancy. 2014.
- Thomson A, Robinson K, The V-TG. 5As: A practical taxonomy for the determinants of vaccine uptake. Vaccine. 2015;34(8):1018–24. doi:10.1016/j.vaccine.2015.11.065.
- Francis MR, Nohynek H, Larson H, Balraj V, Mohan VR, Kang G, Nuorti JP. Factors associated with routine childhood vaccine uptake and reasons for non-vaccination in India: 1998-2008. Vaccine. 2018;36(44):6559–66. doi:10.1016/j.vaccine.2017.08.026.
- Nowak GJ, Cacciatore MA, Len-Rios ME. Understanding and Increasing Influenza Vaccination Acceptance: insights from a 2016 National Survey of U.S Adults. Int J Environ Res Public Health. 2018;15(10). doi:10.3390/ijerph15040711
- Gupta SK, Sosler S, Lahariya C. Introduction of Haemophilus Influenzae type b (Hib) as pentavalent (DPT-HepB-Hib) vaccine in two states of India. Indian Pediatr. 2012;49(9):707–09. doi:10.1007/s13312-012-0151-0.
- MHFW. Shri J P Nadda launches Rotavirus vaccine as part of Universal Immunization Programme; terms it a ‘historic moment’. Bureau PI, ed.. 2016.
- Sachdeva A. Pneumococcal conjugate vaccine introduction in India’s universal immunization program. Indian Pediatr. 2017;54(6):445–46. doi:10.1007/s13312-017-1044-z.
- MHFW. Introduction of measles-rubella vaccine campaign and routine immunization. National Operational Guidelines. Department of Health and Family Welfare. 2017.
- Arya BK, Bhattacharya SD, Sutcliffe CG, Kumar Niyogi S, Bhattacharyya S, Hemram S, Moss WJ, Panda S, Das RS, Mandal S. Impact of Haemophilus influenzae type B Conjugate Vaccines on nasopharyngeal carriage in HIV-infected children and their parents from West Bengal, India. Pediatr Infect Dis J. 2016;35(11):e339–e47. doi:10.1097/INF.0000000000001266.
- Arya BK, Bhattacharya SD, Sutcliffe CG, Ganaie F, Bhaskar A, Bhattacharyya S, Niyogi SK, Moss WJ, Panda S, Ravikumar KL. Nasopharyngeal pneumococcal colonization and impact of a single dose of 13-valent pneumococcal conjugate vaccine in Indian children with HIV and their unvaccinated parents. Pediatr Infect Dis J. 2018 May;37(5):451–58. doi:10.1097/INF.0000000000001800.
- Khan T, Das RS, Arya BK, Chaudhary A, Chatterjee J, Das Bhattacharya S. Impact of pneumococcal conjugate vaccine on the carriage density of Streptococcus pneumoniae and Staphylococcus aureus in children living with HIV: a nested case-control study. Hum Vaccin Immunother. 2020 Jan 29;16(8):1–5. doi:10.1080/21645515.2019.1706411
- Arya BK, Bhattacharya SD, Sutcliffe CG, Saha MK, Bhattacharyya S, Niyogi SK, Moss WJ, Panda S, Das RS, Mallick M. Immunogenicity and safety of two doses of catch-up immunization with Haemophilus influenzae type b conjugate vaccine in Indian children living with HIV. Vaccine. 2016;34(19):2267–74. doi:10.1016/j.vaccine.2016.03.012.
- Heinzen RR, Bridges JF. Comparison of four contingent valuation methods to estimate the economic value of a pneumococcal vaccine in Bangladesh. Int J Technol Assess Health Care. 2008;24(4):481–87. doi:10.1017/S026646230808063X.
- Keja K, Chan C, Hayden G, Henderson RH. Expanded programme on immunization. World Health Stat Q. 1988;41:59–63.
- Lakew Y, Bekele A, Biadgilign S. Factors influencing full immunization coverage among 12-23 months of age children in Ethiopia: evidence from the national demographic and health survey in 2011. BMC Public Health. 2015;15(1):728. doi:10.1186/s12889-015-2078-6.
- Shrivastwa N, Gillespie BW, Kolenic GE, Lepkowski JM, Boulton ML. Predictors of vaccination in india for children aged 12-36 months. Am J Prev Med. 2015;49(6):S435–44. doi:10.1016/j.amepre.2015.05.008.
- Mathew JL. Inequity in childhood immunization in India: a systematic review. Indian Pediatr. 2012;49(3):203–23. doi:10.1007/s13312-012-0063-z.
- Das A, Detels R, Javanbakht M, Panda S. Living with HIV in West Bengal, India: perceptions of infected children and their caregivers. AIDS Care. 2016;29(6):1–7.
- Ndirangu J, Barnighausen T, Tanser F, Tint K, Newell ML. Levels of childhood vaccination coverage and the impact of maternal HIV status on child vaccination status in rural KwaZulu-Natal, South Africa*. Trop Med Int Health TM & IH. 2009;14(11):1383–93. doi:10.1111/j.1365-3156.2009.02382.x.
- Succi RC, Krauss MR, Harris DR, Machado DM, de Moraes-pinto MI, Mussi-Pinhata MM, Ruz NP, Pierre RB, Kolevic L, Joao E. Undervaccination of perinatally HIV-infected and HIV-exposed uninfected children in Latin America and the Caribbean. Pediatr Infect Dis J. 2013;32:845.
- Mast TC, Kigozi G, Wabwire-Mangen F, Sewankambo N, Serwadda D, Gray R, Wawer M, Black R. Immunisation coverage among children born to HIV-infected women in Rakai district, Uganda: effect of voluntary testing and counselling (VCT). AIDS Care. 2006;18(7):755–63. doi:10.1080/09540120500521053.
- Sensarma P, Bhandari S, Kutty VR. Barriers to Immunization Among Children of HIV-Infected Mothers in Kolkata, India A Qualitative Study. Asia-Pacific J Public Health. 2015;27:NP1362–NP71. doi:10.1177/1010539513486177.
- Panda S, Das RS, Maruf SA, Pahari S. Exploring stigma in low HIV prevalence settings in rural West Bengal, india identification of intervention considerations. J Mix Methods Res. 2014;9(4):1558689814535843.
- Castro A, Farmer P. Understanding and addressing AIDS-related stigma: from anthropological theory to clinical practice in Haiti. Am J Public Health. 2005;95(1):53–59. doi:10.2105/AJPH.2003.028563.
- Balasubramanian S, Shah A, Pemde HK, Chatterjee P, Shivananda S, Guduru VK, Soans S, Shastri D, Kumar R. Indian academy of pediatrics (IAP) advisory committee on vaccines and immunization practices (ACVIP) recommended immunization schedule (2018-19) and update on immunization for children aged 0 through 18 years. Indian Pediatr. 2018;55:1066–74. doi:10.1007/s13312-018-1444-8.
- US Department of Health and Human Services. Guidelines for the prevention and treatment of opportunistic infections in HIV-exposed and HIV-infected children. October 2019.
- UIP. Universal immunization program. New Delhi Ministry of health and family welfare. Govt of India; 2014.
- Chamla DD, Essajee S, Young M, Kellerman S, Lovich R, Sugandhi N, Amzel A, Luo C. Integration of HIV in child survival platforms: a novel programmatic pathway towards the 90- 90-90targets. J Int AIDS Soc. 2015;18:20250. doi:10.7448/IAS.18.7.20250.