Thought were cured . The question is whether it really is reactivation or its lowlevel infection that was not detected for a period of time and now is detected. Reporter Martin Hirsch of Massachusetts General Hospital agrees. He says genetics and several other factors affect immune response. Younger people, Healthy People without any underlying conditions are the most likely to develop prolonged antibodies. Reporter with covid19, the World Health Organization says we need more evidence about how effective the antibodies are and how long immunity will last. When were talking about this idea of potentially getting infected for a second time, what time frame would sound reasonable to you for that to make sense . I think those people who test positive then negative and then positive within a few days or a few weeks are almost certainly not reinfected. I think if you go beyond that, a few months, a few years, then you can Start Talking about reinfection. Reporter antibody is not synonymous with immunity. Antibody just tells you youve been infected before. Immunity is more this complex idea. Its a continuum. And it depends on several things. It depends on the number of antibodies you produce, the type of antibodies you produce, so there are neutralizing antibodies. Those are the ones we know work most effectively at neutralizing the virus. You want more of those. It also depends on other parts of the immune system. We have tcells that work with the cells that make the antibodies that help and we have memory cells as well that make antibodies down the road when you see the virus again. That was a lot of science to digest. That was dr. Tara narula reporting. The bottom line is we dont know if you can be reinfected. But thats one concern laying on the minds of thousands of boeing workers who returned to work last week. Kris van cleave has the story. Reporter signs welcome back some of the 27,000 boeing employees returning to work in washington state. Theyre finding a new normal of temperature checks, social distancing, enhanced cleaning procedures, staggered shifts to reduce crowding when people arrive and leave, required mask wearing and for workers who must be close together, theyll be issued p. P. E. Im glad the boeing company is committing to very robust social distancing protocols and use of p. P. E. Reporter boeing says it will use Contact Tracing should someone come down with covid19, but some like this triple 7 mechanic are worried. Are we jumping the gun on this . Most of them are apprehensive thinking its too soon and theyre worried. To be honest with you, theyre very worried. Reporter for boeing its back to work and filling orders and bring in much needed revenue. Its pretty clear people will be looking at boeing. This is one of the steps back to getting people working again. Reporter General Motors employees volunteered to come back to work building ventilators, requiring new procedures that if successful could be valuable Lessons Learned when its time to afet is ourroducti iority we arngy stricocol as i r temperatures, screening, Wearing Masks. Theres cleaning protocols from the start of shift to the end of shift. Reporter ford has hundreds back in factories building ventilators, making respirators and 3d printing face shields. How do you keep your workers from getting each other sick . We have prescreening in place. We will have physical separation for the employees when making our own face shield so well be using that. Reporter boeing officials tell cbs news the health and safety of their employees and their families is the companys priority and their measures are based on federal and state guidance. The cbs overnight news will be right back. When our daughter and her kids moved in with us. Our bargain detergent couldnt keep up. Turns out its mostly water. So, we switched back to tide. One wash, stains are gone. Daughter slurping dont pay for water. Pay for clean. Its got to be tide. Many of you are likely grappling with the challenges of working from home. Well, consider this of the r. Just imagine if your job was on another planet, such as driving the mars rover. Chris martinez has the story. Im matt. Im going to show you my work from home setup. Reporter matt gileners work from home station at home looks relatively relatable for a job that certainly is not. Im the lead rover driver. Reporter rover as in the mars curiosity rover, and gilener is now driving it on the red planet from his living room. Hes part of a 30plus person team that commands the spacecraft. And for the first time ever, all the rovers operations are being handled remotely from makeshift home command centers. Im used to being able to t literally turnover my shoulder and talk to a fellow rover driver. Hey, what do you think of this plan im driving . Instead i have to rely on screen sharing over Network Connections that sometimes can be slow. Reporter still, theyre making it work. So well, in fact, that on the first day of remote operations, the Team Successfully commanded one of the rovers most complicated jobs. Drilling a rock sample on mars. Its kind of an interesting change of pace being able to do the job while you have a pet 3 feet away, or you stop to make lunch in your own kitchen. Reporter the mission so far remaining mostly on schedule, thanks to the teams ability to adapt and their commitment to explore. Chris martinez, cbs news, los angeles. The space may be the only place completely safe from the coronavirus. Mark strassmann spoke to astronaut jessica mere who recently returned to earth after seven months on the International Space station. Reporter from 250 miles above earth, astronaut jessica mere practiced what you could call extreme social distancing. Down below, a planet grappled with a contagion. There were only three people on the space station. It was difficult for us to understand. Wow, we are of the 7 1 2 billion of humans 0 not earth, we are the only three people not affected by this. Reporter that changed a week ago. The capsule brought mere and teammates back to kazakhstan. They landed on a planet somewhat unrecognizable to the one they left. We came back to masked faces. Reporter was that your first corona reality check . Yes. The people pulling us out of the capsule were Wearing Masks the the. Those were the first humans we saw. Reporter while am orbit they achieved a milestone. They performed the first all female space walk last october. That is amazing. Reporter but Long DurationSpace Missions compromise an astronauts immune system. So when mere got back to houston she went into quarantine. Cook had to keep back. From a distance we could do a virtual hug. Its difficult for me. Im a hugger. Ive been up there seven months. Its difficult. Reporter they hope nasa will leave the virus behind. Space exwill receive two astronaut, doug hurley and bob to the International Space station. They will become the First Americans launched from u. S. Soil since 2011 when the Space Shuttle retired. But the corona threat may block their families from watching in person. I would have said emphatically yes a few weeks ago. I think were all just one day at a tiat this point. If not, theyll have to watch it from home potentially. I hone evidently dont know. Reporter jim, nasas administrator, told us this launch will be different. Instead of descending on the Kennedy Space center, this time what were asking people to do is tune in. Watch it on tv. Watch it on the internet. Stay at home. This is a moment in time when all of america can come together in the midst of a pandemic and celebrate something positive. Reporter as for jessica mere, she has something to celebrate. After a week in a quarantine facility, she gets to sleep in her own bed tonight. Do you feel more isolated now than you did when you were orbiting the earth . Yeah, i do. And i think that will come out even more once i do go home. On the space station youre expecting that kind of isolation. Thats just part of the experience. We train for it. We know its there. Here on earth, were not used to that. Reporter like all of us, shes getting used to a different world. Mark strassmann, atlanta. Your bank can be virtually any place you are. You can deposit checks from here. And you can see your transactions and check your balance from here. And pay bills from here. Because your bank isnt just one place. Its virtually any place you are. Just download and use the chase mobile app. Visit chase. Com mobile. A lot of states are relaxing their social distancing guidelines this week, but for the rest of the country, maintaining a safer distance from others while at the same time maintaining our sanity has become an art form. Reporter they set up in i an empty lot and made their way down a river bank just as dawn was breaking. Their boats hit the water at the same time as the sun. Its a great time to paddle so its super pretty. Sunrising, everything is kind of fresh. My favorite thing about being on the water is it makes iteel likeinwr an it is, you know, just as beneficial mentally as it is physically. Reporter erin and joe drove an hour outside of washington to find this peaceful part of the potomac. It lets them ride the rapids without others around. If youre too close to me, im going to hit you with the paddle. Reporter thats a really aggressive method of social distancing. Its effective. I have to meet those cdc guidelines. Reporter americans are heading outside to take a breath, a breath or just a momt toth bu the crowds can make it hard to social distance. And not everyone understands the need for personal space. Which is why kristin hits the track early. Really early. I work at a clinic at 7 30 in the morning so in order to avoid the crowds and still get my workout in, i go before instead of after. Reporter she said sticking to a routine helps her cope with covidrelated stress. Its one of the few things we still can do. I can go run in my Favorite Places. That means a lot to me. Reporter with Favorite Places too packed during the day, these friends have been waiting until after dark to escape their apartments. Riding bikes around d. C. And the deserted national mall. Its nice riding bikes around the city, even when Something Like this isnt happening. Its a great way to see the city and a great way to see the monuments at night. The first time we ever did this, it was the first time things felt peaceful and didnt feel stressful. Reporter and those offhour outings can have other unexpected perks. It was the first time i ever perceived the sky at night in the city. W nicit was therapeutic for su. Reporter of course, its always been there, the sky above the city. It just took a pandemic to see the stars. Christina ruffini, washington. That is the overnight news for this tuesday. Reporting from washington, im jeff pegues. Saptioning sponsored by cbs odonnell tonight, quarantine fatigue. As the death toll in the u. S. Passes 55,000, 19 states loosen restrictions. The governor of california today vows to take action after pictures showing packed beaches. In chicago, outrage after a video shows a house party with hundreds inside. And what cell phone data reveals if americans are still staying home. Ramping up testing. Three months into the crisis, the president unveils what hes calling a blueprint for nationwide testing. And, why President Trump is suggesting some schools open this academic year. C eres the money . Today, Small Businesses get the chance again to apply for help. The federal