BOSTON (CBS) — Dr. Mallika Marshall is answering your coronavirus and coronavirus vaccine-related medical questions. If you have a question, email her or message her on Facebook or Twitter.

Dr. Mallika is offering her best advice, but as always, consult your personal doctor before making any decisions about your personal health.

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“Are the standard COVID tests accurate with variants such as the delta variant?” – Megan

The most reliable COVID test is the PCR test, which is very accurate at detecting the delta variant and other variants. Some rapid tests don’t tend to be as reliable. It is also possible that if a test is performed too early in the course of illness, it may come back negative. If that’s the case, it might be wise to get retested a few days later.

“There is an upcoming rescheduled Fenway concert I have tickets for. I’ve continued masking when out in stores, but the stadium crowd and inability to social distance properly is curbing my enthusiasm.” – Lynn

I think if you’re generally healthy and fully vaccinated, you can still plan on attending outdoor events, like a concert at Fenway, but I would wear a mask when you’re in close proximity to others. If you’re vaccinated, you’re much less likely to get really sick, even from the delta variant, but err on the side of caution and wear a mask .

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“Has anyone experienced headaches after Pfizer for more than five weeks? We’re having that issue with our son.” – Danny

Headaches that occur after the COVID-19 vaccines tend to last only a few days, but there have been anecdotal reports of headaches that linger. That does not mean the vaccines are to blame.

Please talk to your son’s doctor about his symptoms. Perhaps he needs to be referred to a neurologist for evaluation.

“My husband and I have very close friends who are coming to the area. They want us to meet for dinner. We have all been vaccinated, however, they are less cautious than we are. Am I being too cautious in worrying about meeting up with them and having them stay overnight?” – Ann

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We know that people who are fully vaccinated can transmit the delta variant to others, so there is always a small chance that your friends could be infected and pass the virus on to you. I think you’re going to have to weigh the risks and benefits. Speak to your personal physician about your concerns, but if you’re feeling uncomfortable, maybe you can agree to meet them outdoors for dinner but should reconsider an overnight stay.

Dr. Mallika Marshall