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What is it?

Circles is a global protection network against contagious respiratory diseases

Circles was designed to identify and stop the transmission chain of contagious respiratory diseases, without the need of surveillance tracking through GPS or bluetooth. It can be used to:

- Create Protection Circle amongst users who already know each other.

- Allow symptoms self-monitoring.

- Warn direct contacts and indirect contacts (contacts of contacts) when someone voluntarily self-assessed as having a symptom or having been in contact with someone that informed a symptom.

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For Organizations
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Why should you use Circles

We need to be notified as quickly as possible once someone within 3 or 4 levels of separation from us presents symptoms, since most transmissions are pre-symptomatic. Once we get notified we can avoid contact with people in our circle who had contact with the symptomatic person but haven’t developed symptoms yet.

We need Circles because the vaccine will take time to reach the number of people needed to protect everyone else. We know there is no vaccine with 100% effectiveness and not everybody will want to be vaccinated. We still don’t know for how long the vaccine will protect us.
We need to be on the alert for new pandemics. It is clear that we can’t allow  the loss of lives and the economic downturn, specially in vulnerable communities, to happen again. If we maintain a continuous monitoring system we will be able to detect anomalies before the next virus spreads the way sars-cov-2 did. 

Covid-19 is not the only virus related respiratory disease. Once we keep our protection circles activated we will minimize and perhaps block the contamination of other viruses like H1N1.

How does it work?

Circles creates a Global Protection Network Against Contagious Respiratory Diseases by connecting the smaller Protection Circles created by each group of individuals. Each one takes care of its circle and everyone takes care of the network.

4 Simple Steps:


Open circles by clicking on


Invite people to be part of your Circle


Answer periodically if you are feeling well


Protect yourself if you receive an alert that someone is symptomatic

Exposure Status

Black - Low Exposure Risk

Users who answered "no" to having symptoms and "no" to having contact with self-described symptomatic people.

Yellow - Indefinite Exposure Risk

Users who didn't include the original user who invited her/him in their Protection Circle (didn't follow back) and/or users who haven't answered the symptom's question for more than 48 hours.

Orange - Medium Exposure Risk

Users who answered "no" to having symptoms but who had contact (over the last four days) with someone who answered "yes" for symptoms.

Red - High Exposure Risk

Users who informed the system that they have symptoms.

When someone answers "yes" to the symptom question and clicks update, Circles will change its status to Red (High Exposure Risk) and will send a message to everyone in the Protection Circle notifying all users there. All users in this Circle will answer if they had contact with the Red person over the last 4 days. If the answer is "Yes", the system will change this person's color to Orange and will notify its close contacts.


The privacy question is paramount to us. We don't want to live in a world where people's movements and interactions are still more monitored than what they already are.  Therefore, our technology does not access data from the users' GPS or Bluetooth. 

We only gather data needed to establish the Protection Circle between users who already know each other and give permission for the system to connect them. Users only receive status warnings from other users who also added them in their own circles. 

No one has access to names from the second level of protection, contacts of contacts.

When a user answers "yes" for having had contact with someone who is at the orange or red exposure risk list, she/he doesn't inform specifically with whom they were close by. And even if there is only one person on the list, our system does not record the contact between these two people.

Our system only records the user's new status. Our database will never have the information that person A was with person B.

After several iterations we arrived at a balance between privacy and technological efficacy, which is also very important to Adam Kucharsky:  Após várias iterações conseguimos chegar num equilíbrio entre privacidade e efetividade da tecnologia, algo muito importante para o Adam Kucharsky também:  “Whenever my collaborators and I have worked on projects involving movement data, privacy has been hugely important to us. On the one hand, we want to collect the most useful data we possibly can, especially if it could help to protect communities against outbreaks. On the other, we need to protect the private lives of the individuals in those communities, even if this means limiting the information we collect or publish. ” (Kucharsky, pg 505)

Business model

We want Circles to be free for all users and we will not sell data to finance the project. We are certain that Circles will generate huge savings for both private and public Organizations and we believe part of these savings should be channeled to Circles, so the project can survive and evolve constantly. Our team is read to help your organization implement and, if needed, adapt Circles to your reality. Get in touch with us here.

Circles was designed to adapt quickly to the most updated information on pandemic as well as to specific local characteristics.

Any person or organization can support the project. If you want to support as an individual, click here, but if you rather support as an organization, get in touch here.

If you want to offer Circles in organizations with which you have business relationships, please get in touch so we can discuss the terms of your commission.


Marcelo Michelsohn

Works to bring innovation into the real world. He started his journey creating the Sustainable Development department at ABN AMRO Bank in Brazil, Europe and the USA. After that supported family farmers to change their production methods and helped create Cunha's first organic farmers market. He also created a methodology to support thousands of parents navigate the first years of child-parent relationships online.

Diogo Carlotto

Started as a software developer in 1994, moving to web app development in 1999 and artificial intelligence in 2012. While working and developing programming skills, he dedicates a large part of his life to studying economy, sustainability and consumption patterns, creating disruptive initiatives in these areas.

Daniel Carlotto

Started his career working in organizations like Parks, GVT and Dell. He dedicated the past 10 years to enterprises and projects related to the digital world, marketing and innovation.

Over the last 2 years we've been working to develop the first blockchain based distributed economy platform, called Syntropy. We've stopped everything in March 2020 to help in every way we can to contain and minimize the effects of the new coronavirus pandemic.

Institutional support

Semente Negócios, Marcio Jappe

Founder and partner at Semente Negócios, Marcio supports corporations, startups and impact businesses in the adoption of innovative entrepreneurship concepts and tools. He has a Master's degree in Innovation, Technology and Sustainability from UFRGS. He worked as managing director at Artemisia, a consultant at MCKinsey&Co and a sustainability specialist at ABN AMRO Bank in São Paulo and Amsterdam and for Microsoft in Madrid.

Circles' supporting principles

Circles is based on principles first articulated by Diogo Carlotto in this article from April 15th 2020 (in portuguese only) and were validated by the concepts proposed by Adam Kucharsky's book "The Rules of Contagion". O Circles se baseia em princípios articulados pelo Diogo Carlotto neste texto do dia 15 de abril de 2020 que foram validados pelos conceitos propostos por Adam Kucharsky em seu livro "As Regras do Contágio".

Contagion Opportunities and Protection Circle:

According to Adam Kucharsky the number of new infections that an average infectious person will cause is represented by R. This index is found using this equation:  “R = Duration × Opportunities × Transmission probability × Susceptibility”  (Kucharsky, pg 121).

Whenever R is bigger than 1, it means the contagion is increasing. Whenever R is lower than one, the contagion curve is descending. In order to achieve an R lower than 1 we need to reduce all the four factors as much as we can.

Circles works within the Opportunities factor. When our system warns that someone informed having symptoms or being in contact with someone who informed having symptoms, everyone in this person's circle needs to answer whether they had any contact over the last four days.

If a user answers "no", it means she/he didn't have contact with the symptomatic person and therefore will maintain the Low Exposure Risk and will know they shouldn't meet the symptomatic person until at least 14 days after the symptoms disappear.

If a user answers "yes", the risk is raised to Orange (Medium Exposure Risk) and should consult with a doctor or the local health authorities.

The world still doesn't know the percentage of people who will be infectious and never show any symptoms, but we now know that the higher transmission rate happens one to two days before a person shows any symptoms. 

And that's why our system is base on a two level Protection Circle: direct contacts and contacts of contacts. “If we want to predict a person’s risk of infection, it’s not enough to measure how many contacts they have. We also need to think about their contacts’ contacts, and their contacts’ contacts. A person with seemingly few interactions might be just a couple of steps away from a high transmission environment like a school." (Kucharsky, pg 184).

On the drawing above, we can see two Protection Circles with one person in common. That's how Circles create a Protection Network. In this particular case, Edu informed symptoms. Carlos, which doesn't have symptoms informed that the two of them were together less than four days ago. Daniela received a warning that someone n her Circle has had contact with someone who has symptoms. She went to the web platform and saw that Carlos was Orange. They talked to each other and decided to isolate from each other. Two days later, Carlos started having symptoms. That's how Circles predicted Daniela's Exposure Risk before Carlos showed symptoms and interrupted the transmission from Carlos to her.

According to Kucharsky, Carlos was an "interrupter".  This term comes from a gun violence related project but we decided it was useful in our context as well. “The spread of gun violence shares these features: violence is often transmitted through known social links, and the gap between one shooting and the next is long enough for interrupters to intervene. ”(Kucharsky, pg 258).

Since the respiratory diseases contagion is not usually high, Circles sends a quick automated warning the moment someone informs having symptoms or having had contact with a symptomatic person.


Carlotto wrote: "The main idea behind this approach is to offer a smartphone app which will enable protagonism and active participation from people and their social networks. This approach guided us from the beginning.

“The alternative option is to increase transparency. Instead of analysing people’s lives without their knowledge, let them weigh up the benefits and risks. Involve them in the debates; think in terms of permission rather than forgiveness. If social benefits are the aim, make the research a social effort.” (Kucharsky, pg 530)

We believe that people's active participation will allow them to see themselves as part of the solution and not as controlled objects from "outside-in". Participation leads to commitment and allows self-education, since each one needs to think about how to use the system. It also creates self-responsibility for one's own life and for the Protecton Circle's well being.   

Also according to Carlotto, "the self-monitoring questions on the app must:

Firstly, provide the user with an immediate perception of individual benefit, where each interaction results in a clear response of what is the risk of contracting or having contracted any infectious respiratory disease, like Covid-19 or the Flu.

Secondly, create the sensation that with each interaction the person is protecting itself, the people they are close to and society at large.

Thirdly, inform protocols according to the result of the self-monitoring and the Exposure Risk Status.