Nj is dropping mask mandates next week. is it likely safe for vaccinated and boosted ( boosted w/ moderna oct 27 ) 50 somethings with some health issues to stop wearing masks in supermarkets and such?

More than 50% of Americans now have natural immunity so wearing mask is just a reassurance because the chance of infection is low at this time. Unfortunately, third booster dose does not prevent the infection after the exposure but the infection is usually mild. If you want to drop the mask without worry you can ask your doctor a blood test for antibodies from natural immunity and vaccine course.

The covid virus measures ~1 micron in diameter. Cloth masks have pores measuring 50-100+ microns (NIH). Wearing them is more a demonstration of respect for the disease than a preventive measure. Most mask wearing in my state stopped 8 months ago and hospital covid census is 10% of what it was at the peak & predominantly the unvaccinated. Ware if you wish but don't expect it to matter.

Although the numbers are lower than they have been in NJ, if you have medical/health issues, I would recommend you discuss your risk with your doctor. It is still a good idea to wear a KN95 or N95 mask in a crowded indoor space where you don't know everyone's vaccination status. Although our numbers in NJ are going down, they are still not as low as last summer and could certainly rise again.