This is my general opinion only and should only be treated as general advice. Your circumstances may differ.
If you have an investment that is linked to the movement of the share market, and you have maintained your investment stance, moving to a ‘lower risk’ portfolio like cash is problematic for the following reasons:
1) It is possible that you may effectively be locking in your current losses. Sometimes (and indeed in the last week) markets can have their biggest moves the day after significant falls.
2) If you do move to a lower risk portfolio, when do you know when to get back? Although there are many indications that the market is now excellent value, it could still fall further in the current environment. This is known sometimes as ‘catching the knife’.
When the Spanish Flu came after World War 1, markets did not react in the same way. This was because, I think, the war had ended. This goes to valuations. The stockmarket had had an excellent run already and was on some measure over-valued (though valuations were also affected by low interest rates).
So, for many people (and for me), if you have long term investments, I suggest staying the course. This does not mean that your investments will not fall further. But this crisis will eventually pass, and things will get better in the future. Also, it may (or may not) take several years for prices to recover.
At the moment we do not know the trajectory of the virus. When we do have more clarity, I expect that things will get better. There is massive intervention happening from our Central Banks, particularly the Reserve Bank of Australia and the US Federal Reserve.