California is bringing back indoor mask mandates (regardless of vaccination status) in response to climbing coronavirus cases across the state. So, what's the science behind implementing them, especially in a county like San Diego where the vaccination rate is nearly 76% of the eligible population?
“For most people, that's great that the virus isn't going to hurt them. They're vaccinated. They're going to do great. But there are some people who still haven't been vaccinated," explained Davey Smith, M.D., MAS, head of infectious diseases and global public health at UC San Diego. "There are also some people who the vaccine is just not going to work for. And when they come in contact with the virus, they're going to get into real trouble, in which case we could have 76% of the population still vaccinated and still have lots of hospitalizations and deaths."
Though the month-long mask mandate is only for public settings, county data shows over time, household cases are the leading place of exposure followed closely by community settings, social gatherings and non-healthcare workplaces, which are all tied.
Dr. Smith explained how the masking could help when only applied to community settings and not private events.
“Let's say a mask works 10% of the time or 20% of the time. Let's take the bad case scenario that it only works 10% of the time. That means you're protecting 1 out of 10 people who would have gotten infected otherwise. If you're that 1 out of 10, that could be quite a bit," he said.
Health experts say even if you don't want to wear a mask to protect yourself, it'll help you protect others if you're asymptomatic and spreading more than holiday cheer this season.
“It helps protect your loved ones. It helps protect the community and on the grander scale. So even though they're not 100% effective, bulletproof vests are not 100% effective, but you'd still want them if you were in a shootout," said Smith.
A mask-wearing study earlier this year in India, one of the largest of its kind, found that a 30% percent increase in surgical mask-wearing resulted in a nearly 12% reduction in COVID19 cases.