ARBs such as valsartan and losartan may have been very helpful in preventing infection with COVID. The COVID virus portal of entry to a host was by binding with ACE2 receptors in the respiratory tract. The ARBs bind, block and even lessen the number of those receptors.
Yes, this.
Interestingly, when the virus first emerged, some "experts" were worried that ARBs would make the condition worse. These claims made no sense, however. Another term for how the ARBs block the virus from entering the host, and which explains what happens, is "competitive inhibition."