Eroding norms over release of self-spreading viruses.  Science Vol. 375, Issue 6576, pp. 31-33 DOI: 10.1126/science.abj5593

This site is intended to accompany the above publication. Without reading this short article you may find that this website will not make a lot of sense.

The purpose of this site is to contribute towards fostering an informed and public debate about this type of technology 

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(not necessarily written by us)

 Listen to an interview with first author Filippa Lentzos talking with Sarah Crespi host of the Science Magazine podcast about the article.

(start at timepoint 14:00)

Added 30th March 2022  An thoughtful letter by three academics writing from a one-health perspective was posted as an eletter our original published authored article (scroll right to the bottom of the page, or read it here)

Added 27th March 2022  A letter was  published  in the journal Science motivated by our original Policy Forum article , it was authored by the three most prominent proponents of self-spreading vaccines.  In responding we were asked to largely confine ourselves to a number  technical issues many of unclear importance (as least to us), this was also published (our submitted text).  Our preferred, and we hope more constructive, response is also provided here.

media coverage 

Podcast: Science in action,  (timepoint 14:36)

Podcast:Tech & Science daily , lead story

Impfungen, die sich wie ein Virus übertragen: Gefährlich oder die Zukunft?

The controversial quest to make a 'contagious' vaccine

Self-Spreading Vaccine Research Could Spin Out of Control, Experts Warn

The vaccine that spreads immunity by passing itself on like a virus: Researchers investigate potential for self-spreading, needle-less inoculations in wake of Covid pandemic

Expertos alertan del gran riesgo de la vacunación de fauna silvestre en investigaciones para evitar pandemias

How long to midnight? The Doomsday Clock measures more than nuclear risk – and it’s about to be reset again

Les apprentis sorciers du génome

Experten warnen: Sich selbst ausbreitende Impfstoffforschung könnte außer Kontrolle geraten

Vaccines for animals are based on viruses that spread by themselves and are being developed in Europe and the United States.

Greater controls are needed to tackle potential risks from lab-made ‘self-spreading’ viruses

Los expertos advierten que la investigación sobre una vacuna autopropagable podría salirse de control

Tanulmány: kockázatos vírusokat fejlesztenek amerikai és európai laborokban

Researchers are developing viruses that spread vaccines among animal populations

l’UE et les États-Unis suscitent de nouvelles craintes en créant des « virus à risque » pour la recherche sur les vaccins 

ผู้เชี่ยวชาญเตือน: การวิจัยวัคซีนแบบขยายตัวเองอาจหลุดมือ

Safeguards on laboratory-modified viruses ‘inadequate’

Is Risky Research Eroding Norms Over Release Of Self-Spreading Viruses?

Des contrôles plus stricts sont nécessaires pour lutter contre les risques potentiels des virus « auto-propagationnels » fabriqués en laboratoire

Warning: Scientists are creating ‘risky’ self-spreading viruses

Da li je čovječanstvo spremno za zaražavanje vakcinom

Scientists are creating ‘risky’ viruses in labs in US and EU, experts warn

Cientistas estão a criar vírus de auto-propagação como vacinas. Consequências podem ser “irreversíveis”

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An 2020 article on a largely overlapping topic (written by two of the same authors), which uses more accessible language is also freely available from

Scientists are working on vaccines that spread like a disease.


The topic of the Science article is about self-spreading vaccines, but what are they?

This figure contrasts traditionally deployed vaccines that everybody is familiar with, where the vaccine is given separately to each individual, with self-spreading vaccines that are applied to a few individuals and then are intended to spread through the entire population (and ideally to newborn generations). 

How a self-spreading vaccine could work in a bat population. Bats directly injected with a self-spreading vaccine passively spread the lab-modified viral vaccine to other bats they encounter over time (T1->T2->T3…) gradually building up population-wide immunity.  In this example bats are used, but any mammal species that lives in groups could theoretically be targeted to rapidly vaccinate whole populations.

Image credit: Derek Caetano-Anollés

Conventionally deployed vaccines continue to transform our lives protecting us and our domestic animals against many diseases. Self-spreading vaccines are presented as an alternative, but are they a new idea?

No, they are an old idea. 

 In fact the laboratory tools needed to make them have been around for decades. In fact 22 years ago a self-spreading vaccine for rabbits was developed in a laboratory to protect them against two accidentally introduced diseases. This self-spreading vaccine was successfully tested on a Spanish island (see map). Unsuccessful applications were made to the European Medicines Agency for market authorisation of the vaccine. 

Other lab-modified self-spreading  viruses that also aimed to manipulate the immune system of vertebrates were also developed in Australia starting around the 1990s (for more details see FAQ page).

However, no lab-modified self-spreading vaccine has ever been approved to be used in the environment.

Given that in theory self-spreading vaccines are a resource efficient way to vaccinate entire populations, why have they never been approved for use?

In the Science article we propose that this is likely because the vast majority of people working in the fields of virology, evolutionary biology, vaccine development, international law, public health and biorisk-management, think that "laboratory modifications of self-spreading viruses are genetically too unstable to be used predictably in the environment, particularly as mammalian vaccines”. This understanding is based on a  large number of virological studies, and it is this that underlies a longstanding evidence-based norm  against developing viruses  that retain the capacity for self-spreading in the environment.

Numerous regulatory documents generated between 1993 and 2007, including by the World Organization for Animal Health (OIE) and the World Health Organization (WHO) expressed explicit concern at using self-spreading agents for wildlife management. Many or most of the fundamental issues raised remain unresolved in these documents (for more details see FAQ page).

What are the uses of self-spreading vaccines that have been proposed?

Below is text copied from the Science article points 2 and 3 are vaccine based.

This website and the Science article is mostly about the latest cycle of interest in self-spreading vaccines that have been developed through genetic modification techniques. Funding, restarted in 2016 after a 10 year pause after earlier projects were abandoned.

 One of the earliest speculations from the current cycle of interest was in this 2016 PNAS blog post.

From a technical perspective how close are self-spreading vaccines to being assembled? 

As we argue in the Science article, that most or all the techniques being presented as new and capable of generating vaccines that "would spread for only a few hours or days" in the environment have mostly been available to virologists for decades 

 (this includes genome rearrangement, and deletions of viral vector genomes. Only synonymous codon replacement is arguably less that 20 years old, it having first been demonstrated in 2002 or 2006. All of the approaches with the possible exception of genome rearrangement have a proven capacity to stably attenuate live viruses, the question is the extent to which it they can be applied to simultaneously limit viral transmissibility to the extent that they could be perceived as controllable while maintaining sufficient transmissibility to be considered useful as vaccines in continually dynamic environments).

 Consequently, the development / assembly time of self-spreading vaccines can be short. 

 As an example, the time between the very first peer-reviewed description of the Spanish self-spreading rabbit vaccine (see above) and the submission for publication of the results of a successful field trial was just 12 months.

A 2018 report by the Johns Hopkins Center for Health Security included this visual assessment (on page 14) of the, readiness of self-spreading viral approaches to be deployed (X-axis) and their hypothesised impact (Y-axis) to address Global Catastrophic Biological Risks (GCBRS).

The Science article arose from a September 2020 panel discussion at the EuroScience Open Forum which remains available online

This panel dicussion aimed to foster discussion on techniques involving the deliberate releases of GM viruses into the environment and the implications of developments that might be anticipated within the next 2-5 years.  This is done through the perspectives of a  group of panelists from three continents with backgrounds in vaccine hesitancy, virology, evolutionary genetics, biorisk-management, and international law. All of the panelists are Authors on the Science article. Available to watch online at 

For more details on the topic of self-spreading vaccines as an alternative to our increasingly successful conventionally deployed vaccines  please go to the FAQ page of this site

If you are interested in the broader topic of lab-modified self-spreading viruses in the environment (which are proposed to do things other than vaccinate vertebrates) please consider reading this article or look at a companion website on a different type of viral technology.

To contact  authors  of the Science  article use the following  address or links on press release pages above 

Dr. Guy Reeves

Max Planck Institute for Evolutionary Biology, Plön

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