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Intravenous Injection of BCG Works in Monkeys

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发表于 1-4-2020 12:18:05 | 显示全部楼层 |阅读模式
Donald G McNeil Jr, New Technique Makes Old Vaccine for Tuberculosis Far More Effective. New York Times, Jan 2, 2020
https://www.nytimes.com/2020/01/ ... ulosis-vaccine.html

Quote:

(a) "Injecting the vaccine into a vein completely protected nine of 10 monkeys who were exposed to large doses of live TB germs six months later, according to the study. The research was led by scientists from University of Pittsburgh's medical school and the National Institute of Allergy and Infectious Diseases and Published Wednesday Wednesday [Jan 1] by the journal Nature.

(b) "(In this case, 'IV' does not mean a drip, but a quick injection with a thin needle.)

(c) "The tuberculosis vaccine, known as BCG for Bacille Calmette-Guérin after the French scientists who developed it, is made from a live, weakened form of the tuberculosis bacteria found in cattle. It has been in use since 1921, is made by many companies and costs as little as $1 a dose for use in developing countries.

It is considered safe even for newborns [but not so for patients with compromised immunity such as those infected with HIV as well as cancer patients].

"However, it is not very effective. It protects infants against some devastating forms of TB, but eventually wears off and does not protect adolescents or adults against lung infections, the form that kills most TB victims. * ** *'If this is shown to be as efficacious in humans as it is in the monkeys, the potential will be huge,' said Dr Mario C Raviglione, director of University of Milan's Global Health Center and a former director of the World Health Organization's tuberculosis probram.

(d) "Researchers also still need to determine how long the protection lasts, since the monkeys were tested after only six months.

"Also, tuberculosis research in the 1960s showed that injecting just the cell walls of bacteria worked almost as well as injecting whole bacteria.

" 'If cell walls can be tweaked to be as protective, this would be a lot better,” said Dr. Lalita Ramakrishnan, a tuberculosis researcher at the University of Cambridge, because cell walls could not reproduce in someone with a weak immune system.  

(e) "The Nature study tested different ways [normal skin route, inhalation, IV of vaccine; and control (no vaccine)] to deliver the BCG vaccine to six groups of rhesus macaques, which are even more susceptible to TB than people. * * * After six months, only the monkeys injected intravenously were well protected.

(f) "Intravenous administration of BCG vaccine has been tried before. In the late 1960s, researchers tested the idea on a few monkeys and found it to be highly protective.

"But for unknown reasons, they did not pursue that route. The chief authors of those studies * * * have since died.

Note:
(a) Darrah PA et al, Prevention of Tuberculosis in Macaques After Intravenous BCG Immunization. Nature, 577: 95–102 (Jan 1, 2020)
https://www.nature.com/articles/s41586-019-1817-8
("The only available vaccine [for tuberculosis], BCG * * * Two billion people worldwide are infected with Mtb [Mycobacterium tuberculosis: the bacteria causing tuberculosis], with 10 million new cases of active tuberculosis (TB) and 1.7 million deaths each year. * * * T cell immunity is required to control Mtb infection and prevent clinical disease. * * * Intradermal and intramuscular administration—the most common routes of vaccine administration—do not induce high frequencies of resident memory T (TRM) cells in the lung")
(b) BCG vaccine
https://en.wikipedia.org/wiki/BCG_vaccine
("Albert Calmette, a French physician and bacteriologist, and his assistant and later colleague, Camille Guérin, a veterinarian")
(c) macaque
https://en.wikipedia.org/wiki/Macaque
("constitute a genus (Macaca) of gregarious Old World monkeys of the subfamily Cercopithecinae. The 23 species of macaques inhabit ranges throughout Asia, North Africa, and (in one instance) Gibraltar. * * * Aside from humans (genus Homo), the macaques are the most widespread primate genus, ranging from Japan to the Indian subcontinent, and in the case of the barbary macaque (Macaca sylvanus), to North Africa and Southern Europe")
(d) There is no need to read the rest. I am a biologist by training. Everybody in Taiwan has been innoculated with BCG. I thought the immunity was strong and lasted lifelong. I was wrong.
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