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Coronavirus pandemic
This Week in AsiaExplained

Explainer | Can you get the Covid-19 coronavirus twice?

  • So far, research suggests a proportion of people who have had Covid-19 will be protected from another infection – at least initially
  • Scientists are still piecing together information on why some people test positive twice, and why cross-immunity could be important

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A Covid-19 patient lies on a bed at one of the intensive care unit (ICU) of a hospital in Morocco. Scientists are still piecing together information on whether people who have been infected can test positive twice. Photo: AP
Sanjaya Senanayake

Governments are starting to lift restrictions and some are considering “immunity passports”, where all restrictions are lifted for those previously infected.

But are you immune from Covid-19 if you have already been infected?

Some infections never recur once you have had them, such as measles and smallpox. But you can get plenty of others again, such as influenza and tetanus.

So far, research suggests at least a proportion of people who have had Covid-19 will be protected from another infection – at least initially. But the science is far from certain. Here is what we know so far.

First, a quick recap about antibodies

When we encounter an infection for the first time, our body needs to respond quickly to the threat. So within hours, it activates our innate immune system. This system is quick-acting but is not targeted to the specific threat.

The innate immune system’s attack distracts the infection while the body produces a more targeted but slower response against the infection, via the adaptive immune system.

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