---
title: Success of vaccines
tags: live-v0.1, facts
permalink: https://c19vax.scibeh.org/pages/vaxsuccess
---
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# <span style="color:green">Success of COVID-19 Vaccines
:::warning

<span style="color:green">This section is about the success of COVID-19 vaccines in tackling the pandemic. The speedy development of the COVID-19 vaccinations is of course also great success for vaccines. Visit our pages on [the COVID-19 Development Process](https://hackmd.io/@scibehC19vax/vaxprocess) and [Facts About COVID-19 Vaccines](https://hackmd.io/@scibehC19vax/c19vaxfacts) for more about this.
:::

<span style="color:green">Since the first vaccine was administered [outside of a clinical trial in the UK](https://news.sky.com/story/covid-19-uk-patient-becomes-first-in-world-to-receive-pfizer-biontech-coronavirus-vaccine-outside-a-clinical-trial-12154354), over 6.5 billion vaccine doses have been administered globally. There are a range of sources publicly available that have tracked reports of global cases, deaths and total vaccines administered --- showing clearly that the vaccines are reducing deaths, hospitalisations and infection rates.

## <span style="color:green">Finding the data

<span style="color:green"> Whilst both the [World Health Organisation](https://covid19.who.int/?adgroupsurvey={adgroupsurvey}&gclid=Cj0KCQjw5JSLBhCxARIsAHgO2SfGofFwTy9vGt_s_Noj1PAvr4v5MJ_bIJy5fs-VIuex9WTrlj4BGUkaAi8YEALw_wcB) and [CDC](https://covid.cdc.gov/covid-data-tracker/#datatracker-home) publish data, a [collaboration](https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30120-1/fulltext) led by Johns Hopkins University [provides updates in real time](https://www.arcgis.com/apps/dashboards/bda7594740fd40299423467b48e9ecf6) and includes data from China at Province level and at a city level in the USA, Australia and Canada.

<span style="color:green">Additionally, [Our World in Data](https://ourworldindata.org/coronavirus), is an interactive data source which shows how confirmed COVID-19 deaths and hospitalisations have reduced over time since the vaccine roll-out commenced.

### <span style="color:green">Comparing hospitalisations and vaccination rates in Europe and the USA



### <span style="color:green">Comparing Global vaccination rates to infections



<span style="color:green"><sub>Source: Our World in Data, data as at 12th October 2021.

<span style="color:green">The COVID-19 vaccines are estimated to have saved 279,000 lives and averted up to 1.25 million hospitalisations in the [USA](https://www.commonwealthfund.org/publications/issue-briefs/2021/jul/deaths-and-hospitalizations-averted-rapid-us-vaccination-rollout) and in the [UK](https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1016465/Vaccine_surveillance_report_-_week_36.pdf) estimates suggest the prevention of up to 24.9 million infections and up to 116,200 deaths.

<span style="color:green">A recent [French study](https://www.epi-phare.fr/rapports-detudes-et-publications/impact-vaccination-covid-octobre-2021/) of 22.6 million people over the age of 50 reported that vaccination reduces the risk of dying or being hospitalised with COVID-19 by 90%.

<span style="color:green">Research by [McKinsey](https://www.mckinsey.com/industries/healthcare-systems-and-services/our-insights/when-will-the-covid-19-pandemic-end) shows how hospitalisation and death rates in the USA have remained prevalent in the unvaccinated population.

<span style="color:green"><sub>Source: McKinsey

## <span style="color:green">A Systematic Review of COVID-19 Vaccine Efficacy and Effectiveness

<span style="color:green">Whilst there has been an abundance of scientific literature published supporting that the COVID-19 vaccines provide a high degree of protection against infection, disease and death, a [recent review](https://www.medrxiv.org/content/medrxiv/early/2021/09/25/2021.09.17.21263549.full.pdf) of both clinical trial efficacy and real world effectiveness of the vaccines has been released.

<span style="color:green">The review included 21 clinical trial studies of 13 vaccines finding efficacy rates against symptomatic COVID-19 of up to 95% with mRNA vaccines being reported as one of the most effective vaccine technologies.

<span style="color:green">58 real-world effectiveness studies from Israel, the UK, USA, Canada, Chile and Qatar were also reviewed where the Pfizer, Moderna, Johnson and Johnson, Astra Zeneca and CoronaVac vaccines had been administered, with the report summarising that the vaccines are more efficacious at preventing severe infection or death compared to symptomatic COVID-19. The report includes supplementary tables showing effectiveness and efficacy rates across the studies in detail. In summary the review reported protection rates of:

| Vaccine / (Dose) | Death | Severe Infection | Symptomatic Disease | Any Infection | Asymptomatic Infection |
| ---------------- | ------- | ---------------- | ------------------- | ------------- | ---------------------- |
| Pfizer (2) | 90-100% | 85-98% | 80-95% | 65-95% | 65-90% |
| Pfizer (1) | NR | 60-90% | 30-90% | 20-90% | NR |
| Moderna (2) | NR | 90-96% | 87-100% | 85-98% | 92% |
| Moderna (1) | NR | 75-80% | 55-92% | 30-90% | 45-60% |
| AstraZeneca (2) | NR | 75-100% | 65-80% | 60-85% | 15% |
| AstraZeneca (1) | NR | 85-95% | 50-75% | 0-95% | NR |
| CoronaVac* (2) | 80-86% | 85-100% | 65-85% | 66% | NR |
|CoronaVac* (1) | 40-46% | 37% | 16% | 16% | NR |
|Johnson & Johnson (single dose vaccination)| 100%|85%|66% | 12-77% | 65% |

<span style="color:green"><sub>NR= Not reported within the underlying studies subject to the review
<span style="color:green">*Data from Chile only

## <span style="color:green"> Breakthrough Cases and "Long COVID"

<span style="color:green"> In addition to the successes in reducing death, hospitalisation and infection, recent [UK research by the "ZOE" study](https://covid.joinzoe.com/post/double-covid-vaccination-halves-risk-of-long-covid) published in [The Lancet](https://www-sciencedirect-com.glos.idm.oclc.org/science/article/pii/S1473309921004606) has investigated the impact of the COVID-19 vaccines on ['breakthrough cases'](https://www.cdc.gov/coronavirus/2019-ncov/vaccines/effectiveness/why-measure-effectiveness/breakthrough-cases.html). These are cases where COVID-19 is contracted by those who are already vaccinated and generally found in those who live, work or study in areas with a high risk of transmission and where people come into contact with those who are either unvaccinated or who cannot be vaccinated for medical reasons.

<span style="color:green">It is important to remember that these cases are to be expected as no medical intervention, from vaccination to over the counter medication to surgeries can ever be guaranteed as 100% effective. [This article](https://www.theatlantic.com/ideas/archive/2021/08/vaccines-are-still-working-and-theyre-miraculous/619675/) explains how we would naturally expect more breakthrough cases with an increase in vaccination rates.

<span style="color:green">Imagine that 100% of the population world-wide was vaccinated, some would still contract COVID-19, it does not mean that the vaccines are not effective, just that they are not 100% effective.

<span style="color:green">The ZOE study found that in breakthrough cases in adults who receive full vaccination, those adults are 73% less likely to be hospitalised and 31% less likely to experience acute symptoms should they contract a COVID-19 infection. They are also 47% less likely to get "long COVID" which has recently been [classified clinically by the WHO](https://www.who.int/publications/i/item/WHO-2019-nCoV-Post_COVID-19_condition-Clinical_case_definition-2021.1) as "Post COVID-19 condition".

<span style="color:green">*"Post COVID-19 condition occurs in individuals with a history of probable or confirmed SARS CoV-2 infection, usually 3 months from the onset of COVID-19 with symptoms and that last for at least 2 months and cannot be explained by an alternative diagnosis. Common symptoms include fatigue, shortness of breath, cognitive dysfunction but also others and generally have an impact on everyday functioning. Symptoms may be new onset following initial recovery from an acute COVID-19 episode or persist from the initial illness. Symptoms may also fluctuate or relapse over time."*

## <span style="color:green"> Herd Immunity

:::warning

<span style="color:green">To read more about Herd Immunity, please [visit our facts about COVID-19 Vaccines page](https://c19vax.scibeh.org/pages/c19vaxfacts)
:::
<span style="color:green"> Herd Immunity (also referred to as population immunity) is the level of the population that will need to be immune for the virus to stop spreading. This includes immuity from vaccines and natural immunity. At the outset of the pandemic, estimates ranged from [74%](https://www.jmir.org/2021/6/e27632) to [55%](http://medrxiv.org/lookup/doi/10.1101/2020.10.22.20217513). Whilst this will be challenging with access to vaccines varying across countires, [one report](https://news.harvard.edu/gazette/story/2021/02/vaccines-should-end-the-pandemic-despite-the-variants-say-experts/) discusses how this has been achieved in Brazil.

<span style="color:green"> If you are interested in learning how herd immunity works, check out this [YouTube Video](https://www.youtube.com/watch?v=Et_J8_x4qBs) and [this interactive simulator](http://rocs.hu-berlin.de/D3/herd/).

## Previous Vaccine Successes

### Some illustrative cases

Vaccines help children survive and thrive. They save more than [5 lives every minute](https://www.who.int/news-room/facts-in-pictures/detail/immunization), helping people to grow up and grow old in good health. Here are some case studies:

* The eradication of smallpox --- a serious disease that left even [survivors scarred for life](https://www.cdc.gov/smallpox/about/index.html]) ---alone saves an estimated 5 million lives every year. This means that if the vaccine did not exist, a person would now die from smallpox every 6 seconds of every day.


* In the early 1960s, about one-third of African children did not reach the age of 5. Infectious diseases, particularly measles, accounted for a substantial share of these premature deaths ([Greenwood, 2014](https://dx.doi.org/10.1098/rstb.2013.0433)). Even as recently as 1980, measles caused more than 2.5 million deaths globally. Now the incidence of measles has been minimized:


A notable aspect of measles and other childhood diseases is the success of a global campaign launched by the World Health Organisation (WHO) in 1974. This campaign has led vaccine coverage in many low-income countries to rise from less than 5% to 80% or more. At present, 85% of children worldwide [are vaccinated](https://www.who.int/data/gho/data/themes/immunization) against Diphtheria, Tetanus, and Pertussis (whooping cough), and in 125, countries that figure exceeds 90%.

* Polio has been nearly eradicated; the Americas, Europe, South East Asia and the Western Pacific are now [considered polio-free](https://www.cdc.gov/polio/progress/index.htm). The goal to eradicate polio was announced by the WHO in 1988. This has yet to be achieved completely, although there has been a 99.9% drop in the number of polio cases since the start of the eradication program. There were 350,000 cases in 1988 and by 2017 only 22 cases [were reported](https://www.who.int/news-room/q-a-detail/does-polio-still-exist-is-it-curable).


* Whereas 200,000 newborns died from neonatal tetanus in 2000, [by 2018 that number was down to 25,000, an 88% reduction](https://www.who.int/news-room/feature-stories/detail/the-vaccines-success-story-gives-us-hope-for-the-future).

* Ebola is a highly contagious haemorrhagic fever with an average [fatality rate of 50%](https://www.afro.who.int/health-topics/ebola-virus-disease). Fatality rates have varied from 25% to 90% in past outbreaks. The [FDA approved a vaccine in late 2019](https://www.fda.gov/news-events/press-announcements/first-fda-approved-vaccine-prevention-ebola-virus-disease-marking-critical-milestone-public-health). The story of how this vaccine came about makes [fascinating reading](https://www.statnews.com/2020/01/07/inside-story-scientists-produced-world-first-ebola-vaccine/).

[A 2021 study](https://elifesciences.org/articles/67635) led by the [Vaccine Impact Modelling Consortium](https://www.vaccineimpact.org/) assessing the impact of vaccinations against ten infectious diseases (measles, hepatitis B, human papillomavirus (HPV), yellow fever, Haemophilus influenzae type B, Streptococcus pneumoniae, rubella, rotavirus, Neisseria meningitidis serogroup A, and Japanese encephalitis) in 112 different countries found that vaccines given in low- and middle-income countries in the last 20 years are estimated to have prevented 50 million deaths with prevention of a further 47 million deaths predicted between 2020 and 2030 if the vaccination programmes are sustained. Out of the total of 97 million deaths, 52 million are predicted to be in children under the age of five.


_{Source elifesciences.org/articles/67635}

## Want to know more?

A terrific open access article about the history of vaccines and their successes was published by [Brian Greenwood (2014)](https://dx.doi.org/10.1098/rstb.2013.0433).

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:::success
Did you know that vaccines have a long history dating back to [1000 CE](https://www.historyofvaccines.org/timeline/all)? The science of immunology builds on thousands of years of knowledge, and owes a lot to early scientists from so many different cultures.

See our page [here](https://c19vax.scibeh.org/pages/islam) for an example that highlights some of the lesser known, but very important historical contributions that the Islamic world made to science and vaccine development.
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_{Page contributors: Stephan Lewandowsky, Dawn Holford, Michelle Barden}

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