I got this problem where clamav deamon is unable to save a pid in /var/run/clamav/. I also believe that freshclam has a same problem--it should save its pid to /var/run/clamav/freshclam.pid (clamsmtpd could also be affected)

I think the reason for failures is that daemon scripts in /etc/rc.d are creating not /var/run/clamav dir before starting actual processes. My reasoning is based on looking at /etc/rc.d/mysqld, where its script at least checks for the existence of a path where pid will be saved, e.g.
[ ! -d /var/run/mysqld ] && install -d -g mysql -o mysql /var/run/mysqld &>/dev/null

Or could it be that the "-p" options fails to create the dirs under /var/run? e.g.
freshclam -p /var/run/clamav/freshclam.pid
clamsmtpd/etc/clamav/clamsmtpd.conf -p /var/run/clamav/clamsmtpd.pid

I'm just really making educated guesses here, I really know nothing about these scripts.

Solution:
Could we do something like mysqld script does? e.g.
[ ! -d /var/run/clamav ] && install -d -g clamav -o clamav /var/run/clamav &>/dev/null

I originally saw the issue in /var/log/mail.log:
Dec 16 00:04:33 localhost clamsmtpd: couldn't open pid file: /var/run/clamav/clamsmtpd.pid: No such file or directory