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Sent: Sun, Apr 5, 2020 05:12 PM
Subject: Can an Old Vaccine Stop the New Coronavirus? - The New York Times 4/3 online 4/5 print A14
Can an Old Vaccine Stop the New Coronavirus?
A tuberculosis vaccine invented a century ago is cheap and safe, and seems to bolster the body’s immune system.
A vaccine that was developed a hundred years ago to fight the tuberculosis scourge in Europe is now being tested against the coronavirus by scientists eager to find a quick way to protect health care workers, among others.
The Bacillus Calmette-Guerin vaccine is still widely used in the developing world, where scientists have found that it does more than prevent TB. The vaccine prevents infant deaths from a variety of causes, and sharply reduces the incidence of respiratory infections.
The vaccine seems to “train” the immune system to recognize and respond to a variety of infections, including viruses, bacteria and parasites, experts say. There is little evidence yet that the vaccine will blunt infection with the coronavirus, but a series of clinical trials may answer the question in just months.
On Monday, scientists in Melbourne, Australia, started administering the B.C.G. vaccine or a placebo to thousands of physicians, nurses, respiratory therapists and other health care workers — the first of several randomized controlled trials intended to test the vaccine’s effectiveness against the coronavirus.
“Nobody is saying this is a panacea,” said Nigel Curtis, an infectious diseases researcher at the University of Melbourne and Murdoch Children’s Research Institute, who planned the trial. “What we want to do is reduce the time an infected health care worker is unwell, so they recover and can come back to work faster.”
A clinical trial of 1,000 health care workers began 10 days ago in the Netherlands, said Dr. Mihai G. Netea, an infectious disease specialist at Radboud University Medical Center in Nijmegen. Eight hundred health care workers have already signed up. (As in Australia, half of the participants will receive a placebo.)
Dr. Denise Faustman, director of immunobiology at Massachusetts General Hospital, is seeking funding to start a clinical trial of the vaccine in health care workers in Boston as well. Preliminary results could be available in as little as four months.
“We have really strong data from clinical trials with humans — not mice — that this vaccine protects you from viral and parasitic infections,” said Dr. Faustman. “I’d like to start today.”
The B.C.G. vaccine has an unusual history. It was inspired in the 1800s by the observation that milkmaids did not develop tuberculosis. The vaccine is named after its inventors, Dr. Albert Calmette and Dr. Camille Guerin, who developed it in the early 1900s from mycobacterium bovis, a form of tuberculosis that infects cattle.
The scientists cultured bacterial scrapings from cow udders, and continued to culture bovine TB for over a decade until it was weak enough that it no longer caused virulent disease when given to lab animals.
The vaccine was first used in humans in 1921 and was widely adopted after World War II. Now B.C.G. is primarily used in the developing world and in countries where TB is still prevalent, where it is given to over 100 million babies a year.
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Like other vaccines, B.C.G. has a specific target: TB. But evidence accumulating over the past decade suggests the vaccine also has so-called off-target effects, reducing viral illnesses, respiratory infections and sepsis, and appears to bolster the body’s immune system.
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The idea is an offshoot of the “hygiene hypothesis,” which suggests that the modern emphasis on cleanliness has deprived children of exposure to germs. The lack of “training” has resulted in weakened immune systems, less able to resist disease.
One of the earliest studies hinting at the broad benefits of B.C.G. vaccination was a randomized trial of 2,320 babies in Guinea-Bissau in West Africa, published in 2011, that reported that death rates among low-birth-weight babies were dramatically reduced after vaccination. A follow-up trial reported that infectious-disease mortality rates in low-birth-weight babies who were vaccinated were cut by more than 40 percent.
Other epidemiological studies — including a 25-year study of over 150,000 children in 33 countries — have reported a 40 percent lower risk of acute lower respiratory tract infections in children who received a B.C.G. vaccine.
A study in the elderly found that consecutive B.C.G. vaccinations reduced the incidence of acute upper respiratory tract infections.
A recent review by the World Health Organization concluded that B.C.G. had beneficial “off-target effects,” and recommended doing more trials of the vaccine against a wider range of infections.
“This vaccine has saved as many lives as the polio vaccine — it’s an amazing story,” said Dr. Curtis, who designed and launched the B.C.G. trial in Melbourne in less than a month, hoping to stay one step ahead of the coronavirus’s spread in Australia.
While he described the B.C.G. vaccine as underappreciated, he emphasized that it was “not a specific Covid-19 vaccine.” B.C.G. also cannot be administered to anyone who has a compromised immune system, because it is a live-attenuated vaccine — meaning it contains live but weakened TB.
Dr. Faustman said it should not be used in hospitalized patients with active disease, because it may not work fast enough and could interact poorly with other treatments.
Not everyone is convinced B.C.G. holds much promise. Dr. Domenico Accili, an endocrinologist at Columbia University, said he thought efforts to use the vaccine against the coronavirus sound “a bit like magical thinking.”
While acknowledging that B.C.G. is “a non-specific booster of the immune system,” he said, “we should be able to deploy a more tailored approach.”
One question is what effect the vaccine may have in patients whose immune systems overreact to the coronavirus, resulting in what are called cytokine storms. Dr. Randy Cron, an expert on cytokine storms at the University of Alabama at Birmingham, said it was impossible to know.
A recent analysis of the disparate toll the new coronavirus has taken on middle- and high-income countries found a correlation with B.C.G. policies, concluding that countries that did not implement or had abandoned universal B.C.G. vaccination have had more coronavirus infections per capita and higher death rates. (Low-income countries were excluded from the analysis because of unreliable Covid-19 reporting data and generally poor medical systems.)
“You can make a new vaccine,” Dr. Faustman said. “We’re really smart, and we can do that. But it’s two years off, and two years is going to be two years too late.”
“If we’ve got something generic globally at hand that we can use to make the human host stronger, this is a win-win for the public right away.”
Frequently Asked Questions and Advice
Updated April 4, 2020Should I wear a mask?
The C.D.C. has recommended that all Americans wear cloth masks if they go out in public. This is a shift in federal guidance reflecting new concerns that the coronavirus is being spread by infected people who have no symptoms. Until now, the C.D.C., like the W.H.O., has advised that ordinary people don’t need to wear masks unless they are sick and coughing. Part of the reason was to preserve medical-grade masks for health care workers who desperately need them at a time when they are in continuously short supply. Masks don’t replace hand washing and social distancing.
What should I do if I feel sick?
If you’ve been exposed to the coronavirus or think you have, and have a fever or symptoms like a cough or difficulty breathing, call a doctor. They should give you advice on whether you should be tested, how to get tested, and how to seek medical treatment without potentially infecting or exposing others.
How do I get tested?
If you’re sick and you think you’ve been exposed to the new coronavirus, the C.D.C. recommends that you call your healthcare provider and explain your symptoms and fears. They will decide if you need to be tested. Keep in mind that there’s a chance — because of a lack of testing kits or because you’re asymptomatic, for instance — you won’t be able to get tested.
How does coronavirus spread?
It seems to spread very easily from person to person, especially in homes, hospitals and other confined spaces. The pathogen can be carried on tiny respiratory droplets that fall as they are coughed or sneezed out. It may also be transmitted when we touch a contaminated surface and then touch our face.
Is there a vaccine yet?
No. The first testing in humans of an experimental vaccine began in mid-March. Such rapid development of a potential vaccine is unprecedented, but even if it is proved safe and effective, it probably will not be available for 12 to18 months.
What makes this outbreak so different?
Unlike the flu, there is no known treatment or vaccine, and little is known about this particular virus so far. It seems to be more lethal than the flu, but the numbers are still uncertain. And it hits the elderly and those with underlying conditions — not just those with respiratory diseases — particularly hard.
What if somebody in my family gets sick?
If the family member doesn’t need hospitalization and can be cared for at home, you should help him or her with basic needs and monitor the symptoms, while also keeping as much distance as possible, according to guidelines issued by the C.D.C. If there’s space, the sick family member should stay in a separate room and use a separate bathroom. If masks are available, both the sick person and the caregiver should wear them when the caregiver enters the room. Make sure not to share any dishes or other household items and to regularly clean surfaces like counters, doorknobs, toilets and tables. Don’t forget to wash your hands frequently.
Should I stock up on groceries?
Plan two weeks of meals if possible. But people should not hoard food or supplies. Despite the empty shelves, the supply chain remains strong. And remember to wipe the handle of the grocery cart with a disinfecting wipe and wash your hands as soon as you get home.
Can I go to the park?
Yes, but make sure you keep six feet of distance between you and people who don’t live in your home. Even if you just hang out in a park, rather than go for a jog or a walk, getting some fresh air, and hopefully sunshine, is a good idea.
Should I pull my money from the markets?
That’s not a good idea. Even if you’re retired, having a balanced portfolio of stocks and bonds so that your money keeps up with inflation, or even grows, makes sense. But retirees may want to think about having enough cash set aside for a year’s worth of living expenses and big payments needed over the next five years.
What should I do with my 401(k)?
Watching your balance go up and down can be scary. You may be wondering if you should decrease your contributions — don’t! If your employer matches any part of your contributions, make sure you’re at least saving as much as you can to get that “free money.”
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