PROVIDENCE – Even though a single dose of the Pfizer-BioNTech COVID-19 vaccine provides a significant degree of immunity against coronavirus disease, it is imperative that those who have received one return for their second. The same holds true for those who have received only one shot of the Moderna product.

So stated Dr. Ashish Jha on Tuesday during taping of the 27th episode of the “COVID: What Comes Next” podcast. His observation comes amidst reports that some five million Americans have missed their second dose as many experience pandemic exhaustion. 

“One dose alone gives you a high degree of protection,” Jha said, “but here's the ‘but’: We don't think it lasts that long. Ten weeks, maybe 12 weeks, but I certainly have no idea that it will last much longer than that. There's an issue of that durability of protection. So everybody needs a second dose.” 

Feeling that pandemic fatigue and been putting it off?  

Jha, dean of Brown University’s School of Public Health, said no worries.   

Just get the second dose. 

“What I say to folks is, ‘You missed it, that’s not great, ideal to get [the second], but I wouldn't sweat it. Go get your second. You don't have to start all over again. No one's going to be mad at you that you miss the second dose. Just go get your second dose. Everybody needs their second dose of both Moderna and Pfizer.  

“ ‘If you ended up missing at for a couple of weeks because life got busy, you ended up having some work thing or personal thing, don't sweat it. Go get the second dose. Better late than never. One dose does provide some protection but it won't last long enough and you need that second dose.’ ” 

During taping of the podcast, available exclusively from The Providence Journal and the USA TODAY NETWORK, Jha gave the latest update on the pandemic around the U.S. and the planet. It remains a dramatically mixed picture, with some states and nations in relatively good shape while others suffer horrifically.  

“These are some of the worst days globally for the pandemic,” Jha said. “We’re getting close to a million new cases a day happening around the world.” 

The epicenter now is India, where Jha was born and spent his early childhood. That country has now recorded several straight days of some 350,000 or more new cases.  

“Their hospitals are just completely overwhelmed,” Jha said. “People are dying on the streets because they can't get access to oxygen. It is really, really, really bad. And so this weekend, I was thrilled to see the Biden administration step in and say, they're going to help. A lot of other countries are also stepping in. This is a global pandemic. We’ve got to help each other out when other counties get into trouble.” 

Jha also answered an audience question from a woman in Los Angeles who wanted him to address “the very real concerns of the immunocompromised and transplant patient populations with regards to COVID vax protection and risk mitigation. Many of these medically vulnerable adults, myself included, rushed to get the vaccine as soon as it was available to them.” 

Her question: “What advice does Dr. Jha have for the immunocompromised regarding risk mitigation and what understanding does he have of how the vaccine may or may not protect us, i.e. T cells, antibodies, etc.?” 

His answer, in part: 

“There are a group of Americans who have immunocompromised states for a variety of different conditions for whom the vaccines may work less well. The antibody response may be lower. We don't know as much about the T-cell response and so it stands to reason until we have better evidence that these people will have some protection, but not the full degree of protection. It will probably vary by immunocompromised state: different ones will have different levels of response.” 

What can be done? 

“We’ve got to drive the infection numbers down, down, down. We have to get vaccinations numbers really, really high. Because the best way to protect that immunocompromise person with weak protection after vaccination is to make sure that they are exposed to the virus as infrequently as possible.  

“And so, if we can drive infection numbers down to 5,000 or 10,000 infections a day in the United States, it will make it dramatically safer. The alternative is to keep public health restrictions in forever. That's not going to be possible. It's not advisable. I think people will not tolerate it.” 

This weekly podcast is hosted by G. Wayne Miller, health reporter for The Providence Journal.