On one hand, this is good advice based on common sense — get your flu shot, which is even more important in the middle of the COVID-19 pandemic. On the other, though, CDC director Rochelle Walensky offers a contradiction in support of it. Thanks to the masking and social distancing imposed to stop the spread of COVID-19, she argues, the flu didn’t spread much last year, leaving the “herd” less immune this fall and winter. That puts us at greater risk of having both a bad flu and COVID-19 season this year.

Which would be true … if we weren’t still following the same masking and social-distancing mandates/guidelines. Right?

The Washington Post makes a crucial clarification on the risk, which is that it will increase where masks aren’t mandated. But that also leads to another question:

“This low flu activity was likely due to the widespread implementation of covid-19 preventive measures like masks, physical distancing and staying home,” Centers for Disease Control and Prevention Director Rochelle Walensky said in a Thursday briefing announcing flu vaccination efforts.

“Because of so little disease last year, population immunity is likely lower, putting us all at risk of increased disease this year,” she added.

The United States already saw a similar pattern with the spring and summer resurgence of common viruses including respiratory syncytial virus, known as RSV. Hospitals reported surprisingly high numbers of toddlers coming in with severe cases, likely because they were not exposed as infants in the early months of lockdown.

Flu viruses may also roar back with more opportunities to spread this fall and winter in reopened schools, workplaces and businesses, especially where masks are not mandated. Hospitals already battling simultaneous pediatric spikes in covid-19 and RSV fear oxygen and staffing will be stretched thin if flu and coronavirus admissions surge together in the months ahead — a dreaded scenario they avoided during the last winter surge.

Mask mandates didn’t exist in all jurisdictions last year, either. And yet the flu didn’t get around much, largely because people made judicious masking and social-distancing choices even without being ordered to adopt them. We’re still left with the same issue of having the same public regimens that we have over the flu season last year. If that’s the case, should we really expect different outcomes?

It seems highly unlikely that mask mandates will roll back in places that imposed them over the winter last year. Some jurisdictions have in fact re-imposed them more broadly, and a few are now adding proof of COVID-19 vaccination to access higher-density indoor activity (Los Angeles, for instance). Those will likely expand over the fall and winter, especially given the seasonality of COVID-19 and the case-load increases we can expect in colder-weather states. Those just also happen to be mainly states run by Democrats who are much friendlier to mandates.

That’s not to fault Walensky for warning about getting flu shots, which is very good advice in any year, but especially periods as fraught as pandemics. She’s entirely correct to point out that the nation’s health-care system is already heavily burdened with acute COVID-19 cases and can’t afford to absorb a massive influx of flu-related cases at the same time. She’s not even incorrect in the narrowest sense about the herd-immunity risks after a year off from flu spreads. However, if Walensky wants to get into the prediction business, she should note that there seems to be a pretty good chance that we’ll end up without much of a flu spread this year, because masking and social distancing pretty much remains in effect in all the same places as last year.

Get your flu shots, and get vaccinated for COVID-19 if you haven’t already. Prevention is always better than the alternative, and in both cases the vaccine vastly improves the chances of avoiding serious cases of either disease.