#alternate Skip to main content IFRAME: https://www.googletagmanager.com/ns.html?id=GTM-M7H54VD COVID19 * COVID-19 COVAX * COVAX Country Hub * Country Portal Secondary nav * Global Vaccine Summit * Ethics Hotline Donate * Donate * EN * FR Home COVID19 * COVID-19 * EN * FR Main navigation Menu * Our Alliance Our Alliance + About + Strategy o Phase 5 (2021-2025) # The equity goal # The healthy markets goal # The sustainability goal # The vaccine goal o Phase 4 (2016-2020) # The market shaping goal # The sustainability goal # The systems goal # The vaccine goal o Phase 3 (2011-2015) # The financing goal # The health systems goal # The market shaping goal # The vaccine goal o Phase 2 (2006-2010) o Phase 1 (2000-2005) o Risk management o Vaccine investment strategy o Gender and immunisation + Operating model o Gavi's partnership model # The Bill & Melinda Gates Foundation # UNICEF # WHO # The World Bank Group # Civil society organisations # Developing country governments # Developing country pharmaceutical industry # Industrialised country governments # Industralised country pharmaceutical industry # Research and technical institutes o Gavi's business model o Gavi Secretariat o Transparency and IATI + Governance o Gavi Board # Board Committees # Board composition # Board members # Board minutes # Calendar o Governance and legal structures o Corporate Policies o Audit and Investigations + Market Shaping o The Vaccine Innovation Prioritisation Strategy o Supply and procurement roadmaps o Product information for vaccines and cold chain equipment o Vaccine demand forecasting + Global Health & Development o Decade of vaccine collaboration o International Health Partnership for UHC 2030 o Millennium Development Goals o Sustainable Development Goals o UN Global Strategy for Women's, Children's and Adolescents' Health + Work with us o Culture o Vacancies o Internship programme o RFPs and Consulting Opportunities @SaveTheChildren / Hanna Adcock #VaccinesWork Keep informed about the latest topics in global health, including top stories related to the ongoing coronavirus (COVID-19) outbreak. FOCUS AREAS Gavi@20 Progress report Partners Our Board ______________________________________________________________ CAREERS Current vacancies Internship programme RFPs and consulting ______________________________________________________________ Contact us Phishing and fraud * Programmes & Impact Programmes & Impact + How our support works o Support guidelines # Apply for vaccine support # Apply for health system strengthening support # Apply for cold chain equipment support # Report on and renew existing Gavi support # Access targeted country assistance # Additional support guidance documentation o Independent Review Committee o Joint appraisals o Grant performance frameworks o Country portal + Types of support o Vaccine support # Human papillomavirus # Inactivated polio vaccine # Japanese encephalitis # Measles and measles-rubella # Meningitis A # Oral cholera # Pentavalent # Pneumococcal # Rotavirus # Typhoid # Yellow fever o Health system and immunisation strengthening # Immunisation supply chain # Data # Leadership, management and coordination # Demand promotion o Partners' engagement framework # Targeted country assistance # Strategic focus areas # Foundational support o Making immunisation sustainable # Eligibility # Transitioning out of Gavi support # Co-financing o Civil society organisation + Country Hub o Africa # Angola # Benin # Burkina Faso # Burundi # Cameroon # Central African Republic (the) # Chad # Comoros # Congo # Congo, DR # Côte d’Ivoire # Eritrea # Ethiopia # Gambia # Ghana # Guinea # Guinea-Bissau # Kenya # Lesotho # Liberia # Madagascar # Malawi # Mali # Mauritania # Mozambique # Niger # Nigeria # Rwanda # Sao Tome and Principe # Senegal # Sierra Leone # South Sudan # Tanzania, UR # Togo # Uganda # Zambia # Zimbabwe o Americas # Cuba # Haiti # Honduras # Nicaragua # Bolivia # Guyana o Eastern Mediterranean # Afghanistan # Djibouti # Pakistan # Somalia # Sudan # Yemen o Europe # Albania # Armenia # Azerbaijan # Bosnia & Herzegovina # Georgia # Kyrgyzstan # Moldova # Tajikistan # Turkmenistan # Ukraine # Uzbekistan o Southeast Asia # Bangladesh # Bhutan # India # Indonesia # Korea, DPR # Myanmar # Nepal # Sri Lanka # Timor Leste o Western Pacific # Cambodia # China # Kiribati # Lao PDR # Mongolia # Papua New Guinea # Solomon islands # Vietnam + Our impact o Measuring our performance # 2011 - 2015 indicators # 2016 - 2020 indicators o Countries approved for support o Disbursements and Commitments o Evaluation studies # Accelerated Vaccine Introduction project review # ADIPs and Hib Initiative Evaluation # Baseline study for AMC # Co-financing, eligibility and transition policies evaluation 2019 # Cold Chain Equipment Optimization Platform Evaluation # Co-financing Policy Evaluation # Evaluation of Gavi support to CSO 2012 # Evaluation of Gavi support to CSO 2018 # Evaluation of the drivers of urban immunisation in Uganda; Kampala case study (Phase 1) # Full country evaluations # Gavi first evaluation report # Gavi second evaluation report # Gavi support to Albania evaluation # Gavi support to Bosnia and Herzegovina evaluation # Gavi-Government of China Hepatitis B vaccination programme # Gender policy evaluation # Gender policy evaluation 2019 # Health system strengthening evaluations # IFFIm evaluation # Immunisation services support evaluation # Injection safety support evaluation # Measles campaigns in Nigeria # Mid-Term Evaluation of MoU8 # Pneumococcal AMC outcomes and impact evaluation # Pneumococcal AMC process and design # Review of IRCs # Technical assistance through the Partners Engagement Framework evaluation # Using Geospatial Technologies to improve immunisation coverage and equity # Other studies o Facts and figures o Progress reports + Programmatic Policies o Co-financing policy o Eligibility and transitioning o Fragility, emergencies and refugees policy o Gender policy o Health system and immunisation strengthening support framework o Prioritisation mechanism o Risk policy o Self-procurement policy o Transparency and accountability o Vaccine donation policy SUPPORTED COUNTRIES Supported countries Gavi supported a total of 73 countries in 2018 Explore our Country Hub -> FOR COUNTRIES Apply for support Renew support OUR RESULTS Evaluation studies Facts and figures Progress reports * Investing in Gavi Investing in Gavi + Resource mobilisation process o Global Vaccine Summit 2020 o Gavi's Investment Opportunity launch meeting, 30 August 2019 o Gavi Mid-Term Review, Abu Dhabi high level conference, 10-11 December 2018 o Gavi pledging conference January 2015 o Gavi replenishment launch meeting May 2014 o Gavi Mid-Term Review meeting October 2013 o Gavi pledging conference June 2011 o Call for Action and Resources October 2010 o Financing Country Demand March 2010 + Funding o Overview 2000-2037 o Current period 2016-2020 o Donor profiles # Al Ansari Exchange # Alwaleed Philanthropies # Audacious Alliance # Australia # The Bill & Melinda Gates Foundation # Brazil # Canada # The Children’s Investment Fund Foundation (UK) # China Merchants Charitable Foundation # China # Comic Relief # Denmark # ELMA Vaccines and Immunization Foundation # European Commission # France # Germany # Girl Effect # HH Sheikh Mohammed bin Zayed Al Nahyan # Iceland # India # International Federation of Pharmaceutical Wholesalers # Ireland # Italy # Japan # Kingdom of Saudi Arabia # Kuwait Fund for Arab Economic Development # "la Caixa" Banking Foundation # LDS Charities # Lions Club International Foundation (LCIF) # Luxembourg # Mastercard # The Netherlands # Norway # Orange # Other private donors # Principality of Monaco # Reckitt Benckiser Group # Red Nose Day Fund # Republic of Korea # Russian Federation # South Africa # Spain # State of Qatar # Sultanate of Oman # Sweden # Switzerland # Unilever # United Kingdom # United States of America + Partnering with business o Financial partnerships o Leveraged partnerships o Operational partnerships o Become a partner + Innovative financing o IFFIm o Pneumococcal AMC # About the pneumococcal AMC # How it works # Manufacturers # How countries can apply # Timeline # Independent Assessment Committee # AMC legal agreements o Gavi Matching Fund o Loan buydown + INFUSE o INFUSE community o Call for innovations GLOBAL VACCINE SUMMIT World leaders make historic commitments to provide equal access to vaccines for all KEY AREAS Donor profiles Matching Fund Pneumococcal AMC * #VaccinesWork #VaccinesWork + COVID-19 + Country stories + Photo stories + Videos + Opinions + Value of vaccination o Added value o Cost-effective o Health equity o Tried and tested FEATURED STORY Gavi/2020/Benedikt v.Loebell. COVAX explained 3 September 2020 Read more * News & Resources News & Resources + Media room o News releases o Media contacts o Leadership biographies + Audio-visual o Videos o Galleries o Infographics o Presentations + Publications + Document library o COVID-19 situation reports o Evaluations o IRC reports o Financial reports KEY PUBLICATION Gavi innovation catalogue PROGRESS REPORT Download the 2019 Gavi progress report Search _______________ Search Photo by Ryoji Iwata on Unsplash Back to What is herd immunity? The idea of herd immunity as the solution to the COVID-19 pandemic has triggered heated debate, but what is herd immunity and how does it work? 26 March 2020 See how it works Back to What is herd immunity? The idea of herd immunity as the solution to the COVID-19 pandemic has triggered heated debate, but what is herd immunity and how does it work? 26 March 2020 See how it works * Home * #Vaccineswork * What is herd immunity? TOPICS: COVID-19 What is herd immunity? Herd immunity is the indirect protection from a contagious infectious disease that happens when a population is immune either through vaccination or immunity developed through previous infection. IFRAME: https://www.youtube.com/embed/GJhAUAdquXA This means that even people who aren’t vaccinated, or in whom the vaccine doesn’t trigger immunity, are protected because people around them who are immune can act as buffers between them and an infected person. Once herd immunity has been established for a while, and the ability of the disease to spread is hindered, the disease can eventually be eliminated. This is how the world eradicated smallpox, for example. What are the challenges in creating herd immunity? The more infectious a disease, the greater the population immunity needed to ensure herd immunity. For example, measles is highly contagious and one person with measles can infect up to 18 other people. This means that around 95% of people need to be immune in order for the wider group to have herd immunity. IFRAME: https://www.youtube.com/embed/e3iji5Cxtts The new coronavirus has a lower infection rate than measles, with each infected person passing it on to two or three new people, on average. This means that herd immunity should be achieved when around 60% of the population becomes immune to COVID-19. However, natural herd immunity – achieved through infection rather than vaccination – can be challenging to induce through unchecked infection as there would be a very high rate of serious illness and death, with health systems overwhelmed well beyond their surge capacity, even in high-income countries. This is why herd immunity is generally pursued through vaccination programmes. Even when vaccines are available, it is not always possible to achieve herd immunity for very long. Some viruses, such as seasonal flu, mutate frequently, evading the body’s immune response. So immunity doesn’t always last forever, which is why the flu shot is necessary every single year. Risks to herd immunity Mass vaccination has been highly successful in inducing herd immunity for many diseases, protecting those that are unable to build up immunity, such as people with immune deficiencies or whose immune systems are being suppressed for medical reasons. When herd immunity is well established, however, some people choose to behave as ‘free riders’, essentially benefitting from everyone else getting vaccinated, while abstaining from vaccination either because they choose not to or are actively anti-vaccination. When a population has too many of these free riders, the overall immunity level is compromised and herd immunity can be lost, putting everyone at risk. Related Content What COVID Is Costing Women What COVID is costing women GenderCOVID-19 7 December 2020 ©UNICEF/ACQUAH Keeping trust in immunisation during the COVID-19 pandemic COVID-19 4 December 2020 @ UNICEF Uganda/2020/Kabuye Health workers use special days to reach every child with life-saving vaccines Country storiesPhoto storiesCOVID-19 4 December 2020 Science Journal for Kids Routine vaccinations during a pandemic – benefit or risk? COVID-19 3 December 2020 @ UNICEF Uganda/2020/Kabuye “Don’t use COVID-19 as an excuse not to immunize your children, you will regret it.” Country storiesPhoto storiesCOVID-19 3 December 2020 Gavi/2019/Ojwok The COVID-19 vaccine race COVID-19COVAX 2 December 2020 View more Subscribe to our newsletter (BUTTON) Subscribe (BUTTON) First Name ____________________________________________________________ Last Name ____________________________________________________________ Email ____________________________________________________________ Company ____________________________________________________________ Country ____________________________________________________________ Subscribe Leave this field blank ____________________ Home Footer * Our Alliance * Programmes & impact * Investing in Gavi * #VaccinesWork * News & resources Country Hub * Country Portal Donate * Donate Footer nav * Careers * Contact * Ethics hotline * IFFIm * Privacy Policy * Terms of use * Phishing and fraud © Gavi 2020 * Gavi Facebook * Gavi Twitter * Gavi LinkedIn [VSN-logo.png] Our achievements are thanks to the support and expertise of our founding partners