Can you catch coronavirus twice?

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There are fears that it may be possible to catch the coronavirus more than once, after a woman in her 40s in Osaka, Japan, tested positive for COVID-19 for a second time at the end of February. Studies and research are still going on to determine if this may be the case. So far, we do not have a definitive conclusion.
Before understanding whether or not the coronavirus can be caught twice, it is worth knowing how we build immunity to a virus in the first place.
When a pathogen (a foreign infection such as a virus or bacteria) enters the body, the immune system first has to recognise it as alien. There are specific blood cells whose job it is to patrol the body and quickly send out an alert if a new infection is encountered.
This alert stimulates the immune system to start producing very specific antibodies for the infection. This process takes time as a certain level of antibodies need to be produced to overcome the infection.
During this time the virus or bacteria is multiplying, and making you feel unwell as it does so.
It may take a few days or even weeks for your body to get to the level of antibodies needed to fight off the infection, during which time you have the symptoms of infection. When enough antibodies are produced, the infection is overcome and you start to feel better.
The immune system then does something clever: it produces memory cells. These memory cells are ready and waiting should the same infection enter your body again in the future.
If that happens, they are immediately activated and work to destroy the infection before it has time to take hold and make you unwell again. The memory cells also send out a much quicker message to prompt your immune system into action.
In this case, your immune system works so quickly you do not feel unwell or even know you have been infected. This is because you now have immunity to that specific infection.
This immunity usually lasts for life - but not always.

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