Are 'Superspreaders' the Key to Understanding COVID-19 Outbreaks?

A groom in India died 2 days after his wedding because of coronavirus. The 400 guests underwent testing, and 80 of them had positive results. It is believed that the guests were infected during the wedding, and it is very likely that a coronavirus superspreader was the cause.

COVID-19: What is a coronavirus superspreader?

A similar event to the one in India happened last May 30th during a birthday party in Texas. It was reported that a man infected 18 of his friends and family with COVID-19.

Another similar case happened in Washington, where 61 people met for a couple of hours of choir practice. A few weeks later, 53 of them tested positive for COVID-19.

It was discovered later on that during the practice, one of them was already suffering from what they thought was just a cold. It turns out, that person was already infected with COVID-19, and eventually infected the rest of the choir.

These instances are just a few examples of how a coronavirus superspreader can unwittingly infect the people around them. These instances are also known as “superspreading events,” and usually involve large gatherings, or prolonged exposure to infected people.

How does a person become a coronavirus superspreader?

The information that we currently have about coronavirus superspreaders is vague.

We don’t exactly know how a person becomes one, but we do know that some people are more infectious than others. And if a superspreader goes to a large gathering, or continues to stay in contact with other people, it could easily cause another outbreak.

While it is true that superspreaders are more contagious than others, it also has a lot to do with a person’s behavior.

For example, a potential superspreader who is just quarantined at home, and does not interact much with people has a very low chance of spreading the virus to others.

In contrast, a superspreader who does not follow safety protocols, and goes to large gatherings can infect a large number of people.

What makes superspreaders worrisome is the fact that it just takes a few of them to cause an outbreak.

In fact, it is believed that in some areas, 10% of infected people might be responsible for 80% of cases. This is why focusing on superspreaders is an important strategy when it comes to fighting against COVID-19.

COVID-19 infects people in clusters

Influenza tends to infect people slowly and steadily compared to COVID-19. This means that during an outbreak, influenza spreads steadily throughout a population. It does not infect people in clusters.

In contrast, COVID-19 infects people in clusters, rapidly. It doesn’t grow slowly and steadily like influenza. Instead, sudden outbreaks can happen, and some communities might suddenly have an influx of cases without any warning.

This is one of the reasons why COVID-19 is so hard to contain. Because all it takes for an outbreak to happen is for a mass gathering to happen, and then the number of cases suddenly ramp up.

According to Ben Althouse, principal research scientist at the Institute for Disease Modeling in Bellevue, Washington, “You can think about throwing a match at kindling. You throw one match, it may not light the kindling. You throw another match, it may not light the kindling. But then one match hits in the right spot, and all of a sudden the fire goes up. “

Numbers can be misleading

Another important aspect of how COVID-19 spreads is that because it infects in clusters, looking at the average number of infections might not show the whole picture.

For example, one community could have just 10 cases, while a neighboring community could have 50 cases. If you were to just look at the average, it adds up to 30, but it is clear that the second community has five times more infected people than the first one.

It is very likely that a superspreading event was responsible for the higher number of cases in the second community.

And understanding what factors lead to superspreading events and preventing those from happening can significantly lower the chances of future outbreaks.

How can understanding superspreaders prevent future COVID-19 outbreaks?

Based on what we know about prior superspreading events, crowded bars, hospitals, restaurants, offices, public transport and other similar locations are hotspots for superspreading events.

Additionally, large gatherings such as parties, conferences or religious meetings also pose a great risk. This is why lockdowns were effective for other countries.

However, this also means that governments should not get complacent.

One example is Singapore, who did well in controlling the initial wave of infections. However, dormitories where (unscreened) migrant workers stayed suddenly became a hotspot for superspreading events. This meant that they experienced a second wave of infections despite managing to control the first one.

Another important aspect of controlling COVID-19 is to focus on contact tracing and mass testing.

Contact tracing helps authorities identify people who probably came in contact with a superspreader, and they can be tested for coronavirus and advised corresponding quarantine too.

Mass testing can also paint a picture of how many people are infected in one area. This lets authorities know if the area is prone to superspreading events or not. That way, they can devise a strategy around the risk of superspreading events.

Lastly, it is important for all of us to stay safe by avoiding crowds and physical contact with others.

It would be best to avoid mass gatherings for now, and to practice social distancing outside. Wearing masks and washing your hands often can also help lower the risk of future outbreaks.

Learn more about COVID-19, here.