bob wachter.k up where we left off, talking about vaccines and not just the number of people of getting vaccinated but the efficacy because pfizer said the efficacy drops over time. does this mean you're more susceptible to getting covid and being hospitalized? >> it means that efficacy drops, and the data seem pretty clear that six months is the cut off first six months, it works really well, and after six months, you begin to have a drop off in total lack of efficacy, so that means protection against any infections. it does seem to drop a little bit. what we have learned in the last couple of days is a little worrisome when it comes to breakthrough infections, so people have asked me for many months, "why do i even care if i am exposed to covid and get a breakthrough infection? as well as i'm pretty confident i'm not going to get super sick and die, and i remain pretty confident i'm not going to get sick and die." one, the viral levels of people with a breakthrough infection are as high as, or a

majority of california's population lives were indoor masking is recommended once again doctor bob wachterhe ucsf department of medicine and one of the nation's top covid-19 experts is vaccinated. but doctor year again wearing a mask when you go to work indoors is something wrong and have to go back to doing. i think so. >> i think delta become yet another covid curveball. it is twice good at its job. infecting people as the original virus. and so i don't think it was unreasonable for the state to open things up a month or 2 ago before delta took over. but now the delta is taking over. we have to change in response to a much

bob wachter one of the nation's top covid experts. he's vaccinated but wearing a mask again indoors and says you should too. >> because the vaccines still work quite well but the virus i'm likely to be exposed to is this delta virus which is twice as infectious as the original and far more likely i'll be exposed to it today than a month ago. >> reporter: the delta variant is circulating more widely. he doesn't want long term symptoms you can get even after a mild case cognitive individual. lastly, still not enough people are vaccinated nationwide. >> san francisco is essentially 75% vaccinated. two months ago i would have said i think that's maybe high enough to have local herd immunity. that would be high enough to bump down the cases even if people take their masks off. >> reporter: dr. wachter says this surge is must worse. does he think indoor mask mandate is coming back. >> i expect what los angeles did, went back to a mask mandate, i'm guessing the bay area counties will do the same thing in the next couple of weeks. might not i

bob wachter, the head of medicine at ucsf he thinks the bay area will follow los angeles' lead and require mask use indoors. he's vaccinated and is already wearing a mask again indoors and he says you should, too. he says we're much more likely to be exposed to the delta variant which now represents 90% of the cases here in the united states. he doesn't want to catch that and spread it to someone else who would get super sick, and there's still a risk to yourself even if you're fully vaccinated. >> aim not worried about getting super sick, needing to be hospitalized and dying, but we know that people with mild cases of covid sometimes develop what's called long covid and have symptoms that are pretty troubling even months out so i don't want that. now the doctor points out that san francisco is 75% vaccinated, and he says that a couple of months ago he would have thought that that would have been enough to achieve herd immunity locally in the city, but with delta it's not. he says delta has really changed all the facts on the ground. a month ago ucsf had three covid patients. yesterday it

doctor bob wachter is chair of the department of medicine at ucsf and he explains why he thinks it's a good idea to steal double mask in public. >> most of the places i go to. i don't know if there are unvaccinated people and if there and actually people i can't tell whether they're wearing masks or not. so i think it's reasonable to wear a mask. and i think if you're wearing a mask to try to prevent delta, which is much more infectious and the virus we were battling last year. think it's reasonable to wear 2 i do at work. and i do when i go into the store. >> doctor walker says that while we are not ready for a mask mandate in the bay area right now. he believes we could be in the next few weeks. >> san francisco mayor london breed says at this time there are no plans to reinstate a mask mandate. however, she's monitoring and concerning the concerning rise in covid cases right here now health officials say most new cases are among those who are unvaccinated and case rates or 2 and a half times higher among latinos and african americans and they are continuing to urge people who are

majority of california's population lives were indoor masking is recommended once again doctor bob wachter, the chair of the ucsf department of medicine and one of the nation's top covid-19 experts is vaccinated. but doctor year again wearing a mask when you go to work indoors is something wrong and have to go back to doing. i think so. >> i think delta become yet another covid curveball. it is twice good at its job. infecting people as the original virus. and so i don't think it was unreasonable for the state to open things up a month or 2 ago before delta took over. but now the delta is taking over. we have to change in response to a much wily foe. >> so we're going to go back then. even further to when the state was doing that, the color coded tiers. and what was allowed, what was not allowed as that the direction we're headed. >> i hope not. i mean, my hope is that particularly in parts of the state with high vaccination rates like the bay area that a little bit of a step backwards with people being more careful and wearing masks indoors may be enough to get this thing to plateau, but

the study was funded by pfizer and it tested 44,000 people we talked to ucsf doctor bob wachter about what this means for people who have received the vaccine months ago. >> we see that the the efficacy of the vaccines has gotten a little bit lower. >> the good news and it's and lower still in. i suppress station sand and older people in nursing homes. the good news and it's still really good news about the vaccine is that its effectiveness in preventing severe cases seems to be holding up really well, even against delta. so that's if i took one part. one thing that hopeful out of all this. that's what i took. >> the study comes as pfizer continues to push for a 3rd covid vaccine dose to boost immunity. so far the cdc says there's no need for a booster shot at this time. a coalition of south bay nonprofits is finding success in vaccinated homeless people against covid-19 kron four's rob fladeboe was there today as the vaccine was made available at one of the largest homeless camps in san jose. >> enjoying the shade of a tension feeling good about finally being vaccinated against covid

we've got a chance today here at kron 4 to talk with ucsf doctor bob wachter about what this means forple who got the vaccine months ago. >> we see that the the efficacy of the vaccines has gotten a little bit lower. >> the good news and it's and lower still in. i suppressed haitian sand. >> and older people in nursing homes. the good news and it's still really good news about the vaccine is that its effectiveness in preventing severe cases seems to be holding up really well, even against delta. so that's if i took one part. one thing that hopeful out of all this. that's what i took. >> the study coming as pfizer has been pushing for a 3rd covid vaccine dose to boost immunity. so far the cdc says there's no need for a booster shot at this time. >> doctors are turning to a new treatment for those who got the covid vaccine and still test positive for patients who high risk for severe infection. health experts are now turning to fda approved monoclonal antibodies in some cases these a monoclonal antibodies are synthetic versions of the body's own natural line of defense against severe inf

bob wachter, chair of the ucsf department of medicine , tweeted, the delta variant has changed what ittake to reach herd immunity. ucsf lead epidemiologist dr. george rutherford said the state has pushback the goal by several months and that is considered to be a safe estimate. >> herd immunity is a function of how transmissible the viruses. the goalposts have shifted and we are now talking in the mid- 80%. that is not a people eligible for the vaccine, that is everybody. >> according to the vaccine tracker, 53% of the states population is fully vaccinated. san francisco county is at 69%, one of the highest rates in the country. >>> as effort stall for vaccination, president biden is asking people to get their shots . the president spoke at a cnn town hall yesterday. jobina is at the live deskwh go vaccination efforts stall and the delta variant is on the rise. president biden sought to downplay the surge at last night's town hall. he said only unvaccinated people need to worry about the delta variant and urged them to get the shot or shots. but kids under 12 are still not eligible for

bob wachter. he's the chair of uscf department of medicine. we asked him for an plaination.in indoors now and says that you should too for three reasons. the delta variant as i mentioned is circulating more widely now. secondly he doesn't want long term symptoms, something you can get even after a mild case of covid and thirdly lastly there's not enough people vaccinated nationwide. >> san francisco is essentially 75% vaccinated. two months ago i would have said to you i think that's maybe high enough to have local herd immunity. that's high enough to bump down the cases even if people do take their masks off. with delta it's not high enough. that's why we're seeing the surge. delta has changed all of the facts on the ground. >> reporter: yep. dr. wachter says this surge is much worse than the bump he was expecting with the re-opening. he thinks the bay area will follow thread of los angeles and mandate indoor maverick use within the next few weeks. reporting live here in san ramon, bob redell. >> this situation because right here the statewide numbers are inching up as well

bob wachter is here, and he has seen the cdc document. doctor, i appreciate you joining us. warning delta infections are likely more severe. you walked away from it significantly more concerned. tell me why, please. >> yeah, don. everything is a little bit worse than i had understood before i ready the document, when "the washington post" shared it with me about six hours ago. a few things are things that we understood. the vaccinie vaccine efficacy i little bit. that we kind of knew, but the data seems to show that the virus is what they call more infectious than chickenpox. the average person will infect five to eight people versus two to three, which we were used to from the original virus. there's some evidence in the document the severity of delta is higher. that's been a debated point. but at least according to this, the cdc believes that is true. we learned the viral load of people who have been vaccinated and have a breakthrough infection seems to be as high as in people who have non-vaccine related infections, which probably means they are infectious. so it's sort o

doctor bob wachter, thank you so much for your time and thank you. >> fully vaccinated. americans could be able to enter canada next month. prime minister justin trudeau announced today that he is planning to open the border for nonessential travel in mid august and canada is expected to welcome fully vaccinated travelers from all countries by early september. trudeau noted that canada leaves all of that 20 countries in vaccination raise with about 80% of eligible canadians having received at least one dose and more than 50% of eligible canadians fully vaccinated. >> all right. time for a look at the forecast taking a live look, this is the view from mount tam and a lot of fog. yeah. a lot of fog. that means which of course means it is pretty cool out there, and then you're also have some concerns to talk about the possible lightning strikes. yeah. we're watching that closely and all this that time of year we start talking about. >> some of the monsoons and. enough the monsoons don't originated over the area of low pressure. it's usually left over. some tropical moisture

i mean, doctor bob wachter is the chair of the department of medicine at ucsf. by the way, i'm going to say it again. he just heard him say he said double mask. that's what he does. >> so it does make a lot of people wonder it. obviously you all have personal choice until or unless we bury does latest, for example. and we're going to talk to an expert more about what this means and what you should do, what what should you do? look for that. coming up at 8.30. so stay tuned for that live interview. >> in the meantime, let's go to sonoma county where a covid outbreak on at a santa rosa homeless shelter now has force health officials to reopen in alternative care center. >> in order to isolate those people who are getting sick. the first positive cases were first detected at the samuel l jones homeless shelter back on july second and then quickly turned into a large scale outbreak. according to the county 59 people now have tested positive for covid-19. there are 26 other possible positive cases that are being reviewed. 28 of the confirmed cases were from people wh

the study was funded by pfizer and it tested 44,000 people we talked with ucsf doctor bob wachter about what this means for people who received the vaccine months ago. >> we see that the the efficacy of the vaccines has gotten a little bit lower. the good news and it's and lower still you know, suppressed haitian sand and older people in nursing homes. the good news and it's still really good news about the vaccine is that its effectiveness in preventing severe cases seems to be holding up really well, even against delta. so that's if i took one part one thing that hopeful out of all this. that's what i took. >> the study comes as pfizer has been pushing for a 3rd covid vaccine dose to boost immunity. so far the cdc says there's no need for a booster shot at this time. despite rising covid-19 cases. the sonoma county fair is going to go on as planned. the county has over 1000 active cases and they're being blamed on the delta variant. and while the fair will still. feel. and look the same. there are some l% rules in place to make sure people are protected. the fair is requiring people t