This and other numbers in this entry are based on the estimates by the World Health Organisation. The coverage estimates are calculated by dividing the total number of vaccinations given by the number of children in the target population. Target population size is usually based on census population projections.
This means that there may be children in the target population that for medical reasons should be exempt from vaccination. These medical reasons may include factors such as allergies to vaccine components or severe immunodeficiencies.
Notably, such cases are very rare and would have little effect on global coverage numbers. For example, a study from 2003 identified severe allergic reaction in only 0.000063% of all vaccinations, that’s 0.63 cases per million vaccinations. In addition, vaccines are always being improved with fewer ingredients that may cause allergic reactions.
Vaccination of children with immunodeficiencies generally needs to be assessed by a specialist. Especially, for vaccine that are based on a live pathogens. For example, WHO recommends vaccinating HIV-positive children with measles vaccine if child’s HIV infection is asymptomatic or not severe. Similarly, children with severe immunodeficiency syndrome (SCID), a genetic disorder that causes defects in immune system, are safely vaccinated with many vaccines before SCID is even diagnosed, but it’s recommended not to vaccinate them with live vaccines.
In fact, one of the reasons it is important to increase vaccination rates is that those children and adults who for medical reasons cannot be vaccinated would still be protected from diseases through herd immunity.
UNICEF (1996) and Hinman, A. R. (1998) estimate that in the absence of a vaccine the world would have seen 5 million deaths due to smallpox every year in the mid-1990s.
Assuming that the estimate for the mid-1990s provides a midpoint estimate for the period since 1980 and therefore multiplying the 5 million per year estimate by the number of years between 1980 and 2018 means that since the eradication of the disease 190 million people’s lives were saved.
UNICEF (1996) – Vaccines bring 7 diseases under control. Online here.
See Oxford’s Vaccine Knowledge Project for an explanation here: http://vk.ovg.ox.ac.uk/herd-immunity.
Beutels P, Van Damme P, Van Casteren V, Gay NJ, De Schrijver K, Meheus A. The difficult quest for data on “vanishing“vaccine-preventable infections in Europe: the case of measles in Flanders (Belgium). Vaccine. 2002 Oct 4;20(29-
This table is taken from Wikipedia’s entry on Herd Immunity – the original sources are listed there.
Cholera, Dengue fever, Diphtheria, Haemophilus influenzae type b, Hepatitis A, Hepatitis B, Hepatitis E, Human papilloma-virus, Influenza, Japanese encephalitis, Malaria, Measles, Meningococcal disease, Mumps, Pneumococcal disease, Pertussis, Poliomyelitis, Rabies, Rotavirus gastroenteritis, Rubella, Tetanus, Tick-borne encephalitis, Tuberculosis, Typhoid fever, Varicella, Yellow fever, Shingles (Herpes Zoster), and Smallpox.
See https://en.wikipedia.org/wiki/Vaccine-preventable_diseases and https://www.who.int/immunization/global_vaccine_action_plan/GVAP_doc_2011_2020/en/
See Francis EG Cox (2010) – History of the discovery of the malaria parasites and their vectors. In Parasites and Vectors. Online here.
Roush and Murphy (2007) – Historical comparisons of morbidity and mortality for vaccine-preventable diseases in the United States. In the Journal of the American Medical Association, 298, 18, 2155–2163. here
These data are taken from the research paper Roush and Murphy (2007) – Historical comparisons of morbidity and mortality for vaccine-preventable diseases in the United States. In the Journal of the American Medical Association, 298, 18, 2155–2163 here.
The vaccines against the diseases up till ‘Tetanus’ were vaccines licensed or recommended before 1980. The vaccines against the last 5 diseases were only licensed or recommended between 1980 and 2005.
See also ‘Graphical proof that vaccines work (with sources)’ in Medium online here.
To account for such long-term changes, Roush and Murphy (2007) report data from the period shortly before the introduction of the respective vaccine. here
In our graphics and visualizations we rely on the Institute for Health Metrics (IHME) ‘Global Burden of Disease Study 2016’ estimates of child death rates from individual VPDs (compared with other causes), TB death rates across countries, and death rates from individual VPDs; this dataset extends back to 1990 and therefore provides a longer-term perspective on these changes over time. However, lack of estimates from the IHME on the role of vaccination in the prevention of deaths means we rely on WHO data for the number of deaths prevented each year through vaccination and the total amount of deaths VPDs are responsible for.
The rates reported by the WHO and IHME are in a similar range but do differ slightly. WHO data on individual disease death rates can be found here: http://www.who.int/gho/mortality_burden_disease/en/
Note that, as discussed later in this post, the role of vaccines in prevention varies between these causes of death. Measles, for example, has the capacity to be eliminated through vaccination. Diarrheal deaths, in contrast, cannot be eliminated through vaccination alone; hygiene, water services, and nutrition must also be prioritised.
Some countries only give measles vaccines combined with rubella (MR) or with varicella in addition (MMRV).
Highlighted are 10 countries where approximately 60% of these infants live in: Angola, Brazil, the Democratic Republic of the Congo, Ethiopia, India, Indonesia, Iraq, Nigeria, Pakistan, and South Africa.
Zwerling A, Behr MA, Verma A, Brewer TF, Menzies D, Pai M. The BCG World Atlas: A Database of Global BCG Vaccination Policies and Practices. PLoS Medicine. 2011;8(3):e1001012. doi:10.1371/journal.pmed.1001012. Available here.
For a detailed commentary on why we do not yet have an effective TB vaccine see: Davenne T, McShane H. Why don’t we have an effective tuberculosis vaccine yet? Expert Review of Vaccines. 2016;15(8):1009-1013. doi:10.1586/14760584.2016.1170599. Available here.
An affordable MenACWYX vaccine is being developed to cover all the types of meningococcal disease (with the exception of meningitis B, which is available through a separate vaccine) and will also have the ability to be transported at higher temperatures. It is currently in phase 1 clinical trial, with the hope that it will be available for use in 2020–2022.
See Meningococcal disease in the Middle East and Africa: Findings and updates from the Global Meningococcal Initiative, Borrow, Ray et al. Journal of Infection, Volume 75 , Issue 1 , 1 – 11. Available here.
Susan T Goldstein, Fangjun Zhou, Stephen C Hadler, Beth P Bell, Eric E Mast, Harold S Margolis; A mathematical model to estimate global hepatitis B disease burden and vaccination impact, International Journal of Epidemiology, Volume 34, Issue 6, 1 December 2005, Pages 1329–1339, https://doi.org/10.1093/ije/dyi206. Available here.
Smallpox is the only disease that affects humans which has been eradicated through vaccination. Rinderpest, a disease that affected cattle, has also been eradicated. Polio is getting close to being eradicated.
This survey result is in line with the finding of the Gapminder Ignorance Project, which studied Americans’ perception of global vaccination efforts. Just as in the Ipsos Mori survey, the answers that most Americans gave were far off from the truth.
More information on the Gapminder ‘Ignorance Test’ can be found here. The results for the US are here on Gapminder’s site.
The survey results are from Chris Jackson (2017) – Global Perceptions of Development Progress: ‘Perils of Perceptions’ Research’, published by Ipsos MORI, 18 September 2017. Online here.
Terminology: vaccination and immunization
There is a technical difference between vaccination and immunization, as the National Health Service (NHS) explains: “Vaccination means having a vaccine – that is actually getting the injection, or nasal spray or oral vaccine. Immunization means both receiving a vaccine and then becoming immune to a disease”. The distinction is made because in a very small number of those who are vaccinated the vaccination will not ‘take’ and therefore that vaccinated person will not be immunized (i.e. will not be immune to the disease). However, as this refers to a very small number of people both terms are often used interchangeably across the academic literature and in media reporting and we follow this convention in this entry.
For the WHO recommendations see http://www.who.int/ith/vaccines/en/
The Bacille Calmette-Guerin (BCG) vaccine for tuberculosis (TB) is recommended in countries where TB is common. BCG policies and practices have varied considerably across time and countries. The BCG World Atlas is an online resource that tracks these changes comprehensively.
It provides data on topics such as trust in science and scientists; trust in sources of information about health; public understanding of the word ‘science’; the intersection between religious teachings and science; and attitudes to vaccines. In this post, we focus on how attitudes to vaccination vary across the world.
This is a stark result for Venezuela in particular (although perhaps unsurprising) since the availability and coverage of child vaccination has fallen significantly over the last few years.
Navin M. Largent, improving non-medical exemption vaccine policies: three case studies. Public Health Ethics. 2017; 10: 225–234. Available here
Stern, M., Alexandra. (2010). Better Off in School: School Medical Inspection as a Public Health Strategy During the 1918-1919 Influenza Pandemic in the United States
Amin, A.N.E., Parra, M.T., Kim-Farley, R. et al. (2012) – Ethical Issues Concerning Vaccination Requirements. In Public Health Reviews (2012) 34: 14. https://doi.org/10.1007/BF03391666. Online here: https://link.springer.com/article/10.1007/BF03391666
Salmon, Daniel A et al., Compulsory vaccination and conscientious or philosophical exemptions: past, present, and future, The Lancet, Volume 367, Issue 9508, 436 – 442
The data source for vaccination coverage: School Vaccination Assessment Report, 2016-17 school year.
Estimated vaccination coverage with 5 doses of Childhood Diphtheria toxoid, Tetanus toxoid, acellular Pertussis (DTaP) vaccination for kindergartners (typical age range is 4–6 years).
The data source for exemptions is: Immunization Action Coalition, “Exemptions Permitted for State Immunization Requirements,” 2017; LexisNexis; StateNet 2017
Regarding the school vaccination coverage and exemption methods the source notes: “Each school year, school nurses, other school personnel, or health department personnel check the vaccination and exemption status of kindergartners enrolled in public and private schools as required by state law or regulation. State and local immunization programs measure vaccination coverage among children entering kindergarten annually. This may be done for every student or for a sample of students.
State and local areas set the vaccination requirements. Immunization information systems (IISs) may be used as one source of data for school vaccination assessment. The school-level data are reported to the health department. The aggregate data are reported to CDC for public and private schools. Data for home-schooled students are not routinely reported to CDC.”
The types of permitted exemptions vary by state. For specific details refer to School Vaccination Requirements and Exemptions.
See the WHO here.
According to MacKenzie, D. (2011) – Vaccines enjoy a healthy return. New Scientist. Available online.
In 2014 their vaccine business was acquired by GlaxoSmithKline, as reported here.
There are exceptions however. A vaccine for tetanus and diphtheria (td) for example, has a large number of suppliers (13, and 7 for the paediatric formulation).
Review of vaccine price data. Submitted by WHO European Region Member States through the WHO/UNICEF. Joint Reporting Form for 2013. Online here.
The Economist. (2010). A smarter jab. Available online
The Economist. (2010). A smarter jab. Available online
See WHO guidance for more information at: https://www.who.int/vaccine_safety/initiative/tools/DTP_vaccine_rates_information_sheet.pdf
Jaffe, A. B., Lerner, J., Stern, S., & National Bureau of Economic Research. Innovation Policy and the Economy Group. (2006). Innovation policy and the economy. MIT Press. here
The source of the data is the International drug price indicator guide
Bonanni et al. 2009; Bonanni P., Breuer J., Gershon A., Gershon M., Hryniewicz W., Papaevangelou V., et al. (2009) – Varicella vaccination in Europe – taking the practical approach. BMC Med 7: 26 here.
See the WHO here: http://www.who.int/mediacentre/factsheets/fs378/en/
Holt, Ed., Ukraine at risk of polio outbreak, The Lancet , Volume 381 , Issue 9885 , 2244 here
Figures are updated by the WHO here: http://www.who.int/news-room/fact-sheets/detail/measles
See the WHO here: http://www.who.int/mediacentre/factsheets/fs286/en/
In 2014 there were 135.2 million one-year olds. Of these 84.52% received the vaccine against measles.
This means that 135.2 *0.8452 = 114.27 million children were vaccinated.
Gaston De Serres, Jill Sciberras, Monika Naus, Nicole Boulianne, Bernard Duval, and Louis Rochette (1999) – Protection after Two Doses of Measles Vaccine Is Independent of Interval between Doses. In The Journal of Infectious Diseases, Volume 180, Issue 1, 1 July 1999, Pages 187–190, https://doi.org/10.1086/314847 Online here: https://academic.oup.com/jid/article/180/1/187/990623.
For guidelines on recommendations for the second dose of measles vaccine see here https://www.who.int/immunization/sage/meetings/2016/october/Session6-MCV2-Introduction-criteria.pdf
World Health Organization. (2019). Rotavirus. [online] Available at: https://www.who.int/immunization/diseases/rotavirus/en/ [Accessed 14 Aug. 2019].
Ruiz-Palacios, G. M., Pérez-Schael, I., Velázquez, F. R., Abate, H., Breuer, T., Clemens, S. C., … & Cervantes, Y. (2006). Safety and efficacy of an attenuated vaccine against severe rotavirus gastroenteritis. New England Journal of Medicine, 354(1), 11-22.
Vesikari, T., Matson, D. O., Dennehy, P., Van Damme, P., Santosham, M., Rodriguez, Z., … & Shinefield, H. R. (2006). Safety and efficacy of a pentavalent human–bovine (WC3) reassortant rotavirus vaccine. New England Journal of Medicine, 354(1), 23-33.
Troeger, C., Khalil, I. A., Rao, P. C., Cao, S., Blacker, B. F., Ahmed, T., … & Kang, G. (2018). Rotavirus vaccination and the global burden of rotavirus diarrhea among children younger than 5 years. JAMA Pediatrics, 172(10), 958-965.
Aliabadi, Negar, et al. “Global impact of rotavirus vaccine introduction on rotavirus hospitalisations among children under 5 years of age, 2008–16: findings from the Global Rotavirus Surveillance Network.” The Lancet Global Health7.7 (2019): e893-e903.
The cost of rotavirus vaccines varies by country. For example, countries with a gross national income per capita of less than US$1,000 receive subsidies from the Global Alliance for Vaccines and Immunisation, and there the cost per dose is set between US$2.10 – 3.20. With additional co-financing options can reduce the costs down to US$0.13. In high-income countries, such as the US, the cost per dose is between US$70 and 95
Countries are more likely to introduce the vaccine if the political environment is favourably disposed towards them. For example, if a country has set a high priority on achieving the Millennium Development Goal targets or the introduction of vaccines is seen as a positive news story, especially during election years.
Burchett, H. E. D., Mounier-Jack, S., Griffiths, U. K., Biellik, R., Ongolo-Zogo, P., Chavez, E., … & Molla, M. (2012). New vaccine adoption: qualitative study of national decision-making processes in seven low-and middle-income countries. Health policy and planning, 27(suppl_2), ii5-ii16.
World Health Organization (2019). Immunization coverage. [online] Available at: https://www.who.int/news-room/fact-sheets/detail/immunization-coverage [Accessed 14 Aug. 2019].
Clark, Andrew, et al. “Efficacy of live oral rotavirus vaccines by duration of follow-up: a meta-regression of randomised controlled trials.” The Lancet Infectious Diseases (2019).
The Clark et al. (2019) study defined low child mortality rate as less than 1.3% of newborns; medium mortality rate as between 1.35% and 2.81%; and high mortality rate as more than 2.81%
Lamberti, L. M., Ashraf, S., Walker, C. L. F., & Black, R. E. (2016). A systematic review of the effect of rotavirus vaccination on diarrhea outcomes among children younger than 5 years. The Pediatric Infectious Disease Journal, 35(9), 992-998.
Patel, M., Shane, A. L., Parashar, U. D., Jiang, B., Gentsch, J. R., & Glass, R. I. (2009). Oral rotavirus vaccines: how well will they work where they are needed most?. The Journal of Infectious Diseases, 200, S39-S48.
Parker, E. P., Ramani, S., Lopman, B. A., Church, J. A., Iturriza-Gomara, M., Prendergast, A. J., & Grassly, N. C. (2018). Causes of impaired oral vaccine efficacy in developing countries. Future microbiology, 13(1), 97-118.
Troeger, C., Blacker, B., Khalil, I. A., Rao, P. C., Cao, J., Zimsen, S. R., … & Adetifa, I. M. O. (2018). Estimates of the global, regional, and national morbidity, mortality, and aetiologies of lower respiratory infections in 195 countries, 1990–2016: a systematic analysis for the Global Burden of Disease Study 2016. The Lancet Infectious Diseases, 18(11), 1191-1210.
Who.int. (2019) – Immunization coverage. [online] [Accessed 10 Sep. 2019]. http://view-hub.org/viz/ (Go to PCV —> PCV – Vaccine Access —> Children without Access)
Hanada, S., Pirzadeh, M., Carver, K. Y., & Deng, J. C. (2018). Respiratory Viral Infection-Induced Microbiome Alterations and Secondary Bacterial Pneumonia. Frontiers in immunology, 9, 2640.
Song, J. Y., Nahm, M. H., & Moseley, M. A. (2013). Clinical implications of pneumococcal serotypes: invasive disease potential, clinical presentations, and antibiotic resistance. Journal of Korean medical science, 28(1), 4-15.
The number of serotypes included in the vaccine is generally indicated in its name, e.g. PCV13 is pneumococcal conjugate vaccine effective against 13 bacterial serotypes. Vaccines including progressively more serotypes have been introduced over the years, PCV7 was introduced in 2000 and today the most commonly used PCV13 was introduced in 2010.
Hausdorff, W. P., Feikin, D. R., & Klugman, K. P. (2005). Epidemiological differences among pneumococcal serotypes. The Lancet infectious diseases, 5(2), 83-93.
The current non-conjugate vaccine, PPSV23, is generally only given to adults or as a single dose following two immunisations with PCV13 in children older than 2.
Golos, M., Eliakim‐Raz, N., Stern, A., Leibovici, L., & Paul, M. (2016). Conjugated pneumococcal vaccine versus polysaccharide pneumococcal vaccine for prevention of pneumonia and invasive pneumococcal disease in immunocompetent and immunocompromised adults and children. Cochrane Database of Systematic Reviews, (8).
The 27% refers to X-ray-defined cases of pneumonia. For clinically defined pneumonia, a less accurate diagnosis than X-ray-defined cases, the number is 6%. Both of these indicators refer to cases of pneumonia caused by any pathogen not only pneumococcus. Lucero, M. G., Dulalia, V. E., Nillos, L. T., Williams, G., Parreño, R. A. N., Nohynek, H., … & Makela, H. (2009). Pneumococcal conjugate vaccines for preventing vaccine‐type invasive pneumococcal disease and X‐ray defined pneumonia in children less than two years of age. Cochrane Database of Systematic Reviews, (4).
Wahl, B., O’Brien, K. L., Greenbaum, A., Majumder, A., Liu, L., Chu, Y., … & Rudan, I. (2018). Burden of Streptococcus pneumoniae and Haemophilus influenzae type b disease in children in the era of conjugate vaccines: global, regional, and national estimates for 2000–15. The Lancet Global Health, 6(7), e744-e757.
Chen, C., Liceras, F. C., Flasche, S., Sidharta, S., Yoong, J., Sundaram, N., & Jit, M. (2019). Effect and cost-effectiveness of pneumococcal conjugate vaccination: a global modelling analysis. The Lancet Global Health, 7(1), e58-e67.
GAVI (Global Alliance for Vaccines and Immunisation) is a non-profit organisation that provides access to vaccination programs for low-income countries by providing financial support and individual expertise.
O’Brien, K. L. (2018). When less is more: how many doses of PCV are enough?. The Lancet Infectious Diseases, 18(2), 127-128.
For example Kenya has recently entered a transition phase during which it will pay a larger and larger portion of the PCV vaccine cost. By 2027 Kenya will have to pay the full $9 price for a three-dose course child vaccination. The 2016 per capita healthcare expenditure in Kenya was around $66 (5% of the GDP), clearly $9 per child is not a trivial cost.
Simonsen, L., van Wijhe, M., & Taylor, R. (2019). Are expensive vaccines the best investment in low-income and middle-income countries?. The Lancet Global Health, 7(5), e548-e549.
Ojal, J., Griffiths, U., Hammitt, L. L., Adetifa, I., Akech, D., Tabu, C., … & Flasche, S. (2019). Sustaining pneumococcal vaccination after transitioning from Gavi support: a modelling and cost-effectiveness study in Kenya. The Lancet Global Health, 7(5), e644-e654.
The return of investment was estimated for a projected coverage for individual countries for the decade between 2011 and 2020. It means that the economic benefits (as measured by the costs of vaccination program subtracted from the reduced costs of treatment and productivity loss) of using the vaccine are 3 times higher than no vaccine use.
To reduce costs, some countries may also consider switching to a two rather than three dose immunization schedule, but more research on the effectiveness of this schedule in different countries is needed. See O’Brien et al. (2018) reference.
Nakamura, M. M., Tasslimi, A., Lieu, T. A., Levine, O., Knoll, M. D., Russell, L. B., & Sinha, A. (2011). Cost effectiveness of child pneumococcal conjugate vaccination in middle-income countries. International health, 3(4), 270-281.
Ozawa, S., Clark, S., Portnoy, A., Grewal, S., Brenzel, L., & Walker, D. G. (2016). Return on investment from childhood immunization in low-and middle-income countries, 2011–20. Health Affairs, 35(2), 199-207.
Center, I. V. A. (2017). The evidence base for pneumococcal conjugate vaccines (PCVs): data for decision-making around PCV use in childhood. Baltimore (MD): Johns Hopkins University.
Goldblatt, D., Southern, J., Andrews, N. J., Burbidge, P., Partington, J., Roalfe, L., … & Snape, M. D. (2018). Pneumococcal conjugate vaccine 13 delivered as one primary and one booster dose (1+ 1) compared with two primary doses and a booster (2+ 1) in UK infants: a multicentre, parallel group randomised controlled trial. The Lancet Infectious Diseases, 18(2), 171-179.
O’Brien, K. L. (2018). When less is more: how many doses of PCV are enough?. The Lancet Infectious Diseases, 18(2), 127-128.
Adegbola, R. A., DeAntonio, R., Hill, P. C., Roca, A., Usuf, E., Hoet, B., & Greenwood, B. M. (2014). Carriage of Streptococcus pneumoniae and other respiratory bacterial pathogens in low and lower-middle income countries: a systematic review and meta-analysis. PloS one, 9(8), e103293.
Megiddo, I., Klein, E., & Laxminarayan, R. (2018). Potential impact of introducing the pneumococcal conjugate vaccine into national immunisation programmes: an economic-epidemiological analysis using data from India. BMJ global health, 3(3), e000636.
Johnson, H. L., Deloria-Knoll, M., Levine, O. S., Stoszek, S. K., Hance, L. F., Reithinger, R., … & O’Brien, K. L. (2010). Systematic evaluation of serotypes causing invasive pneumococcal disease among children under five: the pneumococcal global serotype project.PLoS medicine, 7(10), e1000348.
World Health Organization. (2010). Changing epidemiology of pneumococcal serotypes after introduction of conjugate vaccine: July 2010 report. Weekly Epidemiological Record [Relevé épidémiologique hebdomadaire], 85(43), 434-436.
Pichichero, M. E. (2017). Pneumococcal whole-cell and protein-based vaccines: changing the paradigm. Expert review of vaccines, 16(12), 1181-1190.
Ginsburg, A. S., Nahm, M. H., Khambaty, F. M., & Alderson, M. R. (2012). Issues and challenges in the development of pneumococcal protein vaccines. Expert review of vaccines, 11(3), 279-285
Kendig, E. L., Wilmott, R. W., & Chernick, V. (2012). Kendig and Chernick’s disorders of the respiratory tract in children. 9th ed. Elsevier Health Sciences.
Rodrigues, L. C., Mangtani, P., & Abubakar, I. (2011). How does the level of BCG vaccine protection against tuberculosis fall over time?. Bmj, 343, d5974.
Rodrigues, L. C., Diwan, V. K., & Wheeler, J. G. (1993). Protective effect of BCG against tuberculous meningitis and miliary tuberculosis: a meta-analysis.International journal of epidemiology, 22(6), 1154-1158.
Sterne, J. A. C., Rodrigues, L. C., & Guedes, I. N. (1998). Does the efficacy of BCG decline with time since vaccination?.The international journal of tuberculosis and lung disease, 2(3), 200-207.
Aronson, N. E., Santosham, M., Comstock, G. W., Howard, R. S., Moulton, L. H., Rhoades, E. R., & Harrison, L. H. (2004). Long-term efficacy of BCG vaccine in American Indians and Alaska Natives: a 60-year follow-up study.Jama, 291(17), 2086-2091.
Daniel A. Salmon, Philip J. Smith, Ann Marie Navar, William K. Y. Pan, Saad B. Omer, James A. Singleton, Neal A. Halsey; Measuring Immunization Coverage among Preschool Children: Past, Present, and Future Opportunities, Epidemiologic Reviews, Volume 28, Issue 1, 1 August 2006, Pages 27–40, https://doi.org/10.1093/epirev/mxj001
”Global childhood immunization coverage growing at only half the officially reported rate, IHME study” online here: http://www.healthdata.org/news-release/global-childhood-immunization-coverage-growing-only-half-officially-reported-rate-ihme
Other vaccines measured by the WHO and UNICEF are HepB3, Hib3, MCV and PAB.
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