Contact tracing

An integral component of the fight against any pandemic is contact tracing, the practice of following transmission chains and breaking them off before a disease is able to spread. In response to the COVID-19 pandemic, contact tracing has been used heavily by many organizations and institutions to help limit the spread of the novel coronavirus. Contact tracers often go through preliminary training to prepare them for their role. I enrolled and completed the COVID-19 Contact Tracing course offered by Johns Hopkins University on Coursera, and in this article, I will summarize the key points of the course so that you, too, can learn about this vital public health tool.

Note: All information in this article is sourced directly from the aforementioned course - I highly recommend you take a look!

Note: Shout out to Stephen Yang for taking the course with me and helping compile this resource!

What is COVID-19?

A coronavirus is an RNA virus that often causes respiratory tract infection. COVID-19 is the disease caused by SARS-CoV-2, and marks the third coronavirus outbreak since 2002, preceded by SARS and MERS. SARS-CoV-2 originated in bats, and mutated to infect and transmit between humans.

There are two ways of detecting if an individual is sick: signs and symptoms. Signs are objective measurements that can characterize illness, such as temperature and breathing rate. Symptoms are qualitative assessments of patient condition, such as aches, loss of taste, or fatigue. COVID-19 commonly presents with fever, fatigue, chills, muscle pain, cough, loss of taste or smell, difficulty breathing, headache, or a sore throat. Patients may present with one or a few of these symptoms, or all of them. Notably, many of these symptoms are nonspecific - they don’t necessarily mean the patient has the coronavirus. In particular, however, loss of taste or smell is specific to COVID-19. Not all infected individuals get sick - we call these individuals asymptomatic.

If a patient presents with increased fever, difficulty or rapid breathing, blue lips or face, shortness of breath, chest pain, confusion, difficulty waking up, or sleep apnea, they must seek immediate care - these are all signs of the patient getting insufficient oxygen and must be treated as soon as possible. COVID-19 kills by attacking and congesting the lungs. Permanent and severe tissue damage can be seen on scans of the lungs of patients.

Certain groups are more likely to have severe disease if infected. People who are old, obese, or have underlying conditions such as diabetes, hypertension, lung disease, heart disease, liver disease, kidney disease, or a weakened immune system are susceptible to becoming severely ill. Young and healthy people, as well as children, are unlikely to become severely ill, but some still do.

How do we diagnose and treat COVID-19?

There are two kinds of tests for COVID-19: diagnostic tests and antibody tests.

Diagnostic tests identify an active virus in the body; these typically employ polymerase chain reaction (PCR) tests that give a sign that the virus is reproducing in your cells. These tests are generally administered via a swab taken from the nose, throat, or mouth.

Antibody tests identify antibodies in the blood, indicating a past infection; these typically employ an IgG antibody test. Typically, these tests never illicit a false positive response, but may illicit false negatives. These tests require blood to be drawn.

Treatment for COVID-19 is an active area of research, as there is currently no specific or effective treatment. Many patients are put on ventilators to help their body get enough oxygen as their lungs fail.

COVID-19 can kill if the lungs do not recover and the patient cannot breathe. The risk of death depends on access to care and general healthiness. Death is most common among older individuals.

How does COVID-19 spread?

First, we should define two periods.

The incubation period is the time between when a person is infected until they present symptoms. COVID-19 has an incubation period between 2 and 14 days, but is usually around 5 days. 5% of cases develop symptoms after 2 days, 50% after 5 days, 95% by 14 days.

The infection period is the time during which an infected person can transmit the virus. The infectious period begins two days before the onset of symptoms, and ends when at least 10 days have passed and symptoms are improving, with no fever in the past 3 days. Asymptomatic individuals can still be infectious.

COVID-19 spread through two primary mechanisms. Firstly, the virus can spread if infected people emit droplets while talking, coughing, or sneezing, that then enter another host through the mouth, nose, and eyes. Secondly, the virus can spread if the virus survives on a physical surface, then enters another host when they touch their mouth, nose, or eyes. Notably, SARS-CoV-2 spreads very efficiently, as it can be transmitted before symptoms show and survive on surfaces for a decent amount of time. Mask use can reduce transmission by reducing the number of droplets an infected person emits.

Transmission is more likely if two individuals have physical contact, close contact, or share an environment. Certain living environments are very conducive to the spread of infection: congregate housing settings such as prisons, dorms, and homeless shelters feature many people living in close quarters. Nursing homes are a “worst-case scenario”, as they often house many old residents in very close quarters. Moreover, they are rarely equipped with enough medical equipment or staff to deal with severe disease.

Other high risk situations include cases that were recently in a high-density environment, cases that are difficult to contact trace, cases that are difficult to isolate or quarantine, and cases that are at high risk of severe disease. In these situations, the disease is much harder to control, and can lead to progressions in community spread. Contact tracers must identify these situations and escalate them to a supervisor immediately.

The reproductive number of any disease, denoted R0 (R-naught), is the average number of people an infected individual will pass the infection on to. SARS-COV-2 has a reproductive number between 2 and 3. For reference, measles has an R0 of 15, MERS has an R0 less than 1, and influenza has an R0 also between 2 and 3. An R0 of 2 can cause an incredibly large outbreak - thus, reducing R0 is an important public health goal.

What is contact tracing?

Left to its own devices, SARS-CoV-2 will spread exponentially - thus, it is a public health imperative that transmission be stopped. Every case of diagnosed COVID-19 requires action: the infected individual requires care, and everyone they have been in contact with must be notified about their exposure, quarantined, and offered support. By tracing the disease and limiting contact between the infected, the possibly infected, and the susceptible, we can limit the spread of COVID-19.

First, some definitions. A case is someone who has COVID-19, usually confirmed by a test. Suspect or probable cases are someone who was exposed to a case, but may not have been tested yet. A contact is someone who had contact with a case while they were infectious. Isolation means keeping sick people separate from healthy people. Quarantine restricts the movement and contact of healthy people who may have been exposed to the disease. To recap: we isolate cases and quarantine contacts.

How long should someone be kept in isolation/quarantine?

A case must be isolated for the duration of their infectious period, until they fully recover. Typically, they should only leave isolation if at least 10 days have passed since the onset of their symptoms, their symptoms are improving, and they have not exhibited a fever in the last 3 days.

A contact must stay isolated for as long as they could be infectious. Typically, they can leave quarantine 14 days after their last contact with an infected individual, granted they are not exhibiting any symptoms. If they have developed symptoms, follow the guidelines for a case.

How do contact tracers investigate cases?

There are six main steps to interacting with a case. Typically, the case will have tested positive for coronavirus, and should already know about their test results. They may be informed of your call in advance.

First, introduce yourself and the situation to the case. Identify the organization you work with and confirm that you are speaking to the correct person by confirming their identity and address. Discuss the positive test, and describe why the call you’re having is beneficial to them and to their family and friends. Let them know that the call is confidential, and ensure that the case is in a safe and comfortable space to talk for about 15 minutes. During your initial conversation, if the case seems to have difficulty breathing or complains about chest pain, get them immediate medical care and return to the later steps when they stabilize.

Second, determine their infection period. Ask them when their symptoms began, if they had a fever, and about their condition now. If they are asymptomatic, ask them when they got tested. Use their response to calculate their infectious period, which you will then use to identify contacts.

Third, identify the case’s contacts. Ask the case who they have seen during their infectious period - this could be people they live with, people they met up with, people they bumped into, or people they passed by. Often, asking them to use a calendar or social media to jog their memory is very effective. If possible, get the contact information for their contacts, and assure them that their identity will not be disclosed to their contacts.

Fourth, issue isolation instructions. Explain isolation to them in simple terms, and then ask questions to ensure that they understood your instructions completely, and to help them plan. Next, identify challenges that they may face during isolation - getting food, paying bills, working, dependents, etc. - that might preclude them from isolating. Offer resources to combat these challenges to ensure a safe and successful isolation.

Fifth, initiate contact tracing. Inform all contact that they were in close contact with a case, and check if they have symptoms. Provide the contact with clear instructions to quarantine, identify challenges they may face during their quarantine, and offer support to combat those challenges.

Sixth, implement regular check-ins with your cases and contacts. Upon each check-in, assess the medical condition of your cases or contact, ask if they’ve seen anyone new since you last checked in, and offer support for their continued isolation.

What are the ethics of contact tracing?

Contact tracing is commonly used to stop the spread of infection, and was used against tuberculosis, syphilis, HIV, and ebola. However, there are concerns surrounding contact tracing and the infringement of privacy, confidentiality, and autonomy rights that we should discuss.

First, definitions. Privacy is defined as the right to be free from intrusion or publicity concerning personal matters - essentially, the right to a personal life. Confidentiality is defined as the right to keep personal medical information private. Autonomy is defined as the right to make one’s own decisions. Justice means to treat people fairly, regardless of their identity. A public good is anything that provides for the well being of the public.

A contact tracer may only ask about private and confidential information for the purposes of contact tracing. Moreover, a contact tracer may request an individual to quarantine or isolate, and in some jurisdictions, this request can be enforced. However, a contact tracer is also obligated to be just, and investigate all cases and contacts equally.

Contact tracing is a public good, as it prevents death and illness. However, we must balance this public good with the rights to privacy, autonomy, and confidentiality. Notably, there is a legal basis for contact tracing efforts: in the US and State constitutions, there are clauses to “protect the public welfare”. This is similar to how vaccinations are mandated for children attending school.

What technology is used to contact trace?

Technology can be used to offset limited resources in contact tracing. Public health staff have limited time and energy, and many contact tracing tasks can be easily automated. Furthermore, contact tracing is an incredibly time-sensitive operation: the window of opportunity to inform a contact about their exposure before they are infectious is incredibly short. Thus, technology can help save lives by making contact tracing more efficient and effective.

Technology can be used to report cases, track symptoms, provide support for isolation and quarantine, help identify contacts quickly, and notify people of test results. Many of these functions are being implemented through SMS, phone applications, or web portals. The use of bluetooth technology to identify nearby contacts and store them in a database is also currently being explored.

There are important considerations to be made when implementing technological solutions to contact tracing. Firstly, not everyone has access to technology or an internet connection, alienating them from what might become a primary means of contact tracing. Moreover, effective intervention depends on public trust and public buy-in: many may be reluctant to install a contact tracing app that tracks their location. No matter the implementation, technological solutions must support, not supersede, traditional contact tracing methods.

How do contact tracers communicate effectively?

Effective communication is essential to building rapport with cases and contacts. When dealing with sensitive subject matter like personal information, mutual understanding and trust is essential. Effective communication entails being assertive, avoiding technical terms, and asking questions one at a time. Being assertive means delivering the information confidently and respectfully - don’t be too passive or too aggressive. Avoiding technical terms like case, contact, or infectious period and asking one question at a time serves to make the conversation more natural to everyone.

Asking personal questions is another important role of any contact tracer. There are 5 basic types of questions: closed questions, used to limit answer choices; open questions, used to generate long, descriptive answers; probing questions, used to get more information about a prior response; checking questions, used to confirm a prior response; and leading questions, used to imply a desired response. Leading questions should be avoided at all costs, and closed questions should be used with care. By leaving the case or contact with the breathing room to respond freely, you can generate higher quality responses that will help accurately identify symptoms and contacts.

Being an active listener entails letting your case or contact know that they are being heard. It deepens your rapport, and encourages them to give vital details about their symptoms and contacts. Tips on being an active listener include paraphrasing what they have said and reflecting their emotions to show that you are listening and understand them. Critically, do not interrupt them or affirm them with phrases like “I know”, when in fact, you do not know. All communication can be boiled down to observations, feelings, needs, and requests. Listening for these parts of communication and responding appropriately is essential to empathic listening and honest expression.

Wrapping up

In this article, we explored the nature of the SARS-CoV-2 virus and the disease it causes, COVID-19. We explored how we diagnose and treat the virus, as well as how it spread. We discussed how contact tracers investigate and inform cases and contacts, encouraging them to quarantine, and we discussed the ethics of such a practice. We closed with a discussion on effective communication, which is vital to effective contact tracing.

I hope that this gives you a basic understanding of what a contact tracer does, as well as some information about the disease on everybody’s mind. I strongly recommend taking the course offered by Johns Hopkins University on Coursera - it is currently free of charge and only 6 hours long.