Even if you’ve had your second dose, you shouldn’t be traveling, experts say. Here are answers to your top Covid vaccine questions.

Let’s “face” it: The answer is no.

Try to think of a face mask as your new best friend, one that you plan to cherish and appreciate for a good, long time. Here are five reasons why.

1) It’s not 100% protection. Even the best of the currently available vaccines only offer up to 95% protection when you are fully immunized. That means there is a 5% chance you can catch the novel coronavirus at any time.

2) Everyone’s different. Some people are going to mount more robust immune responses to both rounds of the Covid-19 vaccination than others. That’s one of the key reasons experts are insisting everyone receive the second shot of the vaccine within a key time frame.

“So the major reason for the second dose is to get everybody to respond. If you just get a single dose, you don’t really know where you stand,” Hotez said.

Remember, it can take two to three weeks after you get the second shot before your immunity fully kicks in.

3) A moving target. As is typical with viruses, the SARS-CoV-2 virus is mutating around the world — creating variants that are proving to be more contagious than those the US is currently battling.

Experts are already warning that antibodies from a prior case of Covid-19 won’t protect against being reinfected with a variant from South Africa.

“If it becomes dominant, the experience of our colleagues in South Africa indicate that even if you’ve been infected with the original virus that there is a very high rate of reinfection,” Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, told CNN’s Wolf Blitzer on Monday. “Previous infection does not seem to protect you against reinfection.”

There is also a possibility that the current vaccines won’t fully protect against the new variants of the SARS-CoV-2 virus. That’s being studied feverishly right now, so stay tuned.

That scenario could apply to Covid-19.

“We don’t yet know whether being vaccinated means that you’re no longer a carrier of coronavirus. That is, fully immunized people may still be able to spread Covid-19 to others,” said CNN Medical Analyst Dr. Leana Wen, an emergency physician and visiting professor at George Washington University Milken Institute School of Public Health.

5) Will immunity last? Researchers don’t yet know just how long the immunity given by the current vaccines — such as it is — will last. There is a possibility that booster doses may be needed in the months or years to come. That’s not uncommon — adults need tetanus and diphtheria boosters every 10 years.

So until more is known about how long the protection lasts — and against which variants — stay safe and protect others by wearing a mask.

When can I hang out with friends and family?

That depends on everyone’s vaccine status, experts say. If friends or other members of your family have also received both doses of a Covid-19 vaccine, the risk is greatly reduced, especially if the visit is outdoors.

“It’s probably pretty safe to see others who were also vaccinated, after everyone gets both doses and waits a few weeks,” Wen said.

It would also be safe if the unvaccinated friends or family members or friends quarantined for 10 days before the outdoor get-together.

However, if the visit is indoors, “there is going to be some level of risk,” Wen said, especially with the current spread of more contagious variants and the less than 100% efficacy of today’s vaccines.

“That risk will be much lower than if you were not vaccinated, but the risk is still going to be there to you, and you could still be a risk to the unvaccinated members of your family, as you could be an asymptomatic carrier who transmits to them,” Wen said.

“If you really want to spend time with the grandkids indoors, the safest way to do this is still for everyone to quarantine for at least 10 days and lower their risk during these 10 days,” Wen said. “Quarantining for seven days and a negative test is an option too, but everyone also has to do the quarantine — a negative test alone is not enough.”

And again, just because you’ve been vaccinated, that doesn’t reduce your responsibility. You should continue to wear a mask and practice social distancing whenever you are around others.

“You wouldn’t want to engage in activities where you could potentially acquire the novel coronavirus and then transmit it to others,” Wen said.

“That includes seeing other people who are vaccinated, but not wearing a mask — based on what we know now, they could have the virus and pass it onto you, and you could pass it onto the people you live with. An abundance of caution is still a good idea.”

When can I eat at an indoor restaurant or go to a concert or sporting event?

Indoor restaurants are likely hotspots for Covid-19 transmission. That’s partly because no one is wearing a mask while they eat, thus spreading their respiratory droplets around as they socialize.

So even with a second vaccine, you’re still taking a chance that you might be exposed to Covid-19 and become a silent spreader.

But won’t the typical 6-foot spread between tables or booth partitions do the trick?

“I think the 6 feet indoors is not enough by itself,” said Linsey Marr, a professor of civil and environmental engineering at Virginia Tech, who has been studying Covid-19 transmission.

“You have to have good ventilation in that bar or restaurant,” said Marr, the co-author of a paper on airborne transmission of Covid-19 via very small droplets called aerosols.

However, even a HEPA filter wouldn’t make environmental engineer Marr feel comfortable eating inside a restaurant. In order for the filter to protect you, the virus-laden air would have to pass through the air handling system and be filtered first before it gets to you, she said.

“HEPA filters reduce the amount of virus in the background air, but most transmission takes place in these close contact type of scenarios where you’re near someone that’s infected and they’re spreading lots of virus. The HEPA filter doesn’t help with that,” she said.

“And since I can’t wear a mask while I’m eating, I’m just avoiding indoor restaurants until this is over,” Marr said.

What about fun things to do, such as concerts and sporting events?

“Once vaccinated, an outdoor sporting event or concert is probably safe, if there is good social distancing between households and everyone is wearing masks,” Wen said. “Indoor, crowded gatherings are probably still best to avoid even if you’re vaccinated.”

Can I travel if I’ve been vaccinated?

And that applies to people who have already been vaccinated, added Fauci, the White House chief medical adviser.

“Getting vaccinated does not say now I have a free pass to travel,” Fauci said at the CNN global town hall. “Nor does it say that I have a free pass to put aside all of the public health measures that we talk about all the time.”

“I mean, if you absolutely have to travel and it’s essential, then obviously, one would have to do that. But we don’t want people to think because they got vaccinated, then other public health recommendations just don’t apply,” Fauci said.