The Knowledge Hub

What is the Knowledge Hub?

Explore the VoICE Knowledge Hub—a searchable database featuring the latest peer-reviewed research on immunization benefits, especially in low- and middle-income countries. Browse the Knowledge Hub using a variety of different filters to find vaccine evidence based on country, region, topic, or disease. Click on a tag to find more evidence on a specific area, such as the return on investment of vaccines or impacts of infectious disease outbreaks.


Diseases & Vaccines


WHO Regions


Immunization Terms

Influenza vaccination for healthcare workers reduced sick days during flu seasons

Healthcare workers who received an influenza vaccine missed fewer days of work compared to non-vaccinated peers (1.74 vs 2.71 days/person). The study took place at a large Italian hospital that employed approximately 5,300 healthcare workers. The researchers examined a severe influenza season (2017/2018) as well as three moderate flu seasons (2010-2013).

Gianino MM, Kakaa O, Politano G et al.. 2021. Severe and moderate seasonal influenza epidemics among Italian healthcare workers: A comparison of the excess of absenteeism. Influenza and Other Respiratory Viruses. 15(1).

Influenza vaccination reduces absenteeism among healthcare workers

In a retrospective cohort study among healthcare workers (HCWs) of an Italian academic healthcare trust during the 2017–2018 influenza season, non-vaccinated HCWs lost 2.47/100 person-days of work compared to 1.92/100 person-days of work among vaccinated HCWs (p < 0.001). This adds further evidence that absenteeism among HCWs is negatively correlated with influenza vaccination.

Antinolfi F, Battistella C, Brunelli L et al.. 2020. Absences from work among healthcare workers: are they related to influenza shot adherence?. BMC Health Services Research. 20(1).

Increasing influenza vaccine uptake can help manage respiratory outbreaks and reduce strain on healthcare systems during COVID-19

The potential for a spike in COVID-19 concurrent with influenza season could threaten to overwhelm healthcare systems, particularly in resource-limited contexts. A double burden of influenza and COVID-19 cases could also increase risk of cross-infection and transmission in hospital settings. This mathematical modeling study found that increasing influenza vaccine uptake would help manage respiratory outbreaks coinciding with peak flu season and thus reduce the potential strain on healthcare systems responding to COVID-19.

Li Q, Tang B, Bragazzi NL et al.. 2020. Modeling the impact of mass influenza vaccination and public health interventions on COVID-19 epidemics with limited detection capability. Mathematical Biosciences. 325.

Integrating family planning and immunization services in Malawi was found to be feasible and beneficial

In this mixed-methods implementation study, routine immunization and family planning services were integrated across health facilities and community sites across two rural districts in Malawi, Dowa and Ntchisi. The total number of women accessing family planning services during the study period increased by 14% while DPT immunization rates for children remained consistent. In interviews, parents and providers found the integration of family planning and immunization services to be feasible and beneficial, indicating a win-win for both services.

Cooper CM, Wille J, Shire S et al.. 2020. Integrated Family Planning and Immunization Service Delivery at Health Facility and Community Sites in Dowa and Ntchisi Districts of Malawi: A Mixed Methods Process Evaluation. International Journal of Environmental Research and Public Health. 17(12).

Children born in a health facility are more likely to receive full vaccinations compared to those born at home

A study in Ghana using nationally representative survey data found that children born in an institutional setting had a substantially higher proportion of full vaccination (73.9%) compared to those born at home (60.8%). Children born in a health facility—either public or private—had 1.71 times the odds of receiving a full vaccination schedule compared to children born at home.

Moran EB, Wagner AL, Asiedu-Bekoe F et al.. 2020. Socioeconomic characteristics associated with the introduction of new vaccines and full childhood vaccination in Ghana. Vaccine. 38(14).

Seasonal flu programs help countries prepare for pandemics and reduce the burden of flu

Seasonal influenza programs can be cornerstones to pandemic preparedness and response. Using the 2009 WHO Vaccine Deployment Initiative as a case study, eligible countries with a seasonal influenza vaccine program were more ready to receive and use donated vaccines than those without a program. These findings suggest that robust seasonal influenza vaccine programs allow countries to test crucial regulatory and delivery systems that enhance pandemic preparedness while also reducing the substantial burden of seasonal influenza.

Porter RM, Goldin S, Lafond KE et al.. 2020. Does having a seasonal influenza program facilitate pandemic preparedness? An analysis of vaccine deployment during the 2009 pandemic. Vaccine. 38(5).

Attending antenatal care visits increases the likelihood of fully immunized children in Nigeria and other countries

Mothers in Nigeria were between 2-4 times more likely to have fully immunized children if they attended 1-3 antenatal care (ANC) visits, between 2.5-8 times more likely if they attended 4-7 ANC visits, and between nearly 3-14 times more likely if they attended at least 8 ANC visits compared to those who had no ANC.

Similar findings have been seen in many LMICs, including Senegal, Bangladesh, Indonesia, India, Zimbabwe, and Southwest Ethiopia.

Anichukwu OI, Asamoah BO. 2019. The impact of maternal health care utilisation on routine immunisation coverage of children in Nigeria: A cross-sectional study. BMJ Open. 9(6).

Mothers who received proper care during and after childbirth were more likely to have fully immunized children

Mothers who had skilled birth attendance and post-natal care were approximately 6 times were likely to have fully immunized children.

Anichukwu OI, Asamoah BO. 2019. The impact of maternal health care utilisation on routine immunisation coverage of children in Nigeria: A cross-sectional study. BMJ Open. 9(6).

Investments in polio eradication in Africa improved overall immunization systems and increased coverage of routine vaccinations

A systematic review of 8 African countries that had wild polio virus transmission and significant polio eradication activities found evidence that the huge investments made in polio have strengthened capacity in almost all aspects of the overall immunization systems, especially in the areas of microplanning, service delivery, capacity-building (especially supportive supervision and on-the-job training), and program management. This led to substantial increases in coverage of other routine vaccinations – BCG, DPT, measles – in all 8 countries over a 25-year period (1989-2014), including a more than a 3-fold increase in DPT3 coverage in 2 countries and a more than a 2-fold increase in 3 other countries.

Anya BPM, Moturi E, Aschalew T et al.. 2016. Contribution of polio eradication initiative to strengthening routine immunization: lessons learnt in the WHO African region. Vaccine. 34(43).

Immunization campaigns against measles and rubella have improved routine immunization systems and disease prevention measures

A survey of 23 countries in all WHO regions found that activities to eliminate measles and rubella, including vaccination campaigns, have strengthened the countries’ overall routine immunization systems in a number of ways. These include microplanning that led to revised catchment populations and denominators for target-age children, expansion of cold chain systems that extended the reach of immunization, strengthening of surveillance and of outbreak preparedness and response for vaccine-preventable and other diseases.

Biellik RJ, Orenstein WA. 2018. Strengthening routine immunization through measles-rubella elimination. Vaccine. 36(37).