Straight to the point

I was today made aware of this article reporting on an ongoing clinical trial of a new TB vaccine (M72/AS01).

“The vaccine aims to prevent adolescents and adults already infected with latent TB from developing pulmonary TB.

In countries with high TB burden, vast numbers of people have latent TB, which means that they are infected with the TB bacteria but not symptomatic or infectious.

People with latent TB do not generally develop TB disease unless their immune systems are compromised.”

So the target is “latent TB” – which is not symptomatic, it’s not infectious, and doesn’t progress unless the person is immunocompromised.

So of course, we need mass vaccination.

Completely unsurprisingly, “the Gates Medical Research Institute (Gates MRI)…is sponsoring the trial, while funding comes from the Gates Foundation and Wellcome Trust.

Incidentally, the article states that “A Phase 2b trial of the vaccine found that it was 50% effective in blocking latent TB from becoming pulmonary TB”.

The publication for that trial can be found here. A quick perusal reveals that:

• If 1000 were vaccinated, 3 cases of active TB per year would be prevented
• The duration of any protection is unknown – mean follow-up by the time of publication was 2.3 years
• Though the protection was 54%, the trial was small so the the 95% confidence interval is wide – consistent with protection as low as 2.9%
• In terms of all-cause outcomes the text of the main paper states this:

Fatigue, headache, malaise, or myalgia was each reported by 58.1%-68.9% of M72/AS01_E recipients and 26.5%-47.0% of placebo recipients.

Fever >38.0°C was reported by 18.9% and 6.6%, respectively. Fever >39.5°C was uncommon (4.1% versus 1.3%, respectively).

However, buried in the supplement it seems that “respiratory symptoms” were more than twice as common in the vaccinated group compared to placebo (19.6% vs 8.6%).

This seems an odd thing to omit to mention, especially given that the target disease is (mainly though not exclusively) regarded as a respiratory infection. Note that the reduction in the occurrence of the progression of latent to active TB was stated to be from 0.6% down to 0.3%, so the increase in the occurrence of respiratory symptoms in absolute terms dwarfs this by a factor of >361.

It’s worth remembering that in those who DO develop active TB, this can, of course, be successfully treated anyway.

Republished with permission from Jonathan’s Substack

Source: PANDA Read the original article here: https://pandata.org/