Typhoid Mary

Asymptomatic ‘Typhoid Marys’ could be causing 50% of new COVID-19 cases

Colin Garner Coronavirus COVID-19, Learn more

People who are infected with coronavirus (COVID-19) but do not fall ill are increasingly believed to be spreading the infection far and wide. That’s why we needed the Government measures to contain the outbreak to come weeks earlier than they did.

‘Typhoid Mary’, or Mary Mallon, was the first documented person with typhoid to show no symptoms. The first infamous ‘super spreader’, we now know that she infected more than 50 people with typhoid. All she did to spread the infection was to go about her daily life, just like we have been trying to do for weeks. Sadly, three of those people died of typhoid, and many of the others will have gone on to further spread the disease. So why are we letting history repeat itself during the COVID-19 outbreak?

Mass testing

The World Health Organisation calling for mass testing. Doing so has seen South Korea handle the outbreak with exceptional efficacy. A similar project in Iceland has shown that around half of the people who tested positive are showing no symptoms, too. Mass testing is the example we should be following here in the UK. This should be followed by tracking and quarantining the people who have been in contact with those found to have the virus. We need to be able to identify asymptomatic coronavirus carriers to further limit the spread.

People are quarantining themselves without medical intervention if their symptoms are mild. As a result, we have very little idea of how many such cases there are. Current data, though limited, suggests the number of asymptomatic carriers and those showing mild symptoms is in the hundreds of thousands in the UK. In addition to testing to see who has this infection, we should also be carrying out antibody tests to see who has previously been exposed to it, and is now likely immune, as covered in yesterday’s blog.

Without extensive testing, we are allowing our ‘Corona Marys’ to their key worker jobs. Asymptomatic coronavirus carriers will pick up groceries for their elderly neighbours and mingle with their housemates. Things will only get worse once restrictions are lifted.

Key takeaway: We need to carry out stringent testing to find out who is or is not spreading coronavirus. When it comes to fighting a virus as contagious and virulent as this one, knowledge is power. Ignorance means many more people will die.