I applied online. I interviewed at NIH (Croton-on-Hudson, NY) in Dec 2020
Interview
It was nice and encourage others to apply. All you need to is submit the application through their website before December. Good luck to those applying and even though you do not get do not beat yourself up about it.
Other Summer Research Intern interview reviews for NIH
The interview was very straightforward. I was asked several behavioral questions about my previous experiences and coursework. The interviewer was very friendly and mostly just wanted to know why I wanted the position.