Old vaccine against new virus

Old vaccine against new virus

Some vaccines not only protect against a specific disease, but also strengthen the immune system as a whole. Can this be used to fight the Sars-CoV-2 coronavirus?

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When measles vaccination was introduced in the Congo, Senegal and Guinea-Bissau, child mortality decreased by a good half. That was significantly more than just preventing measles.

The old polio vaccine, which was given as a swallowing vaccine, not only protected against polio, but also reduced the risk of contracting the flu, among other things, a research team said in a recent article in the science magazine “Science“indicates.

Various other studies confirm that so-called live vaccines can also protect against pathogens, against which they are not specifically targeted, through unspecific effects. Live vaccines contain weakened pathogens that are still able to reproduce. This is no longer the case with so-called inactivated vaccines; the positive side effects are no longer attributed to them.

The authors led by Konstantin Chumakov from the US drug agency FDA are now advocating the use of polio vaccination (OPV) as a coronavirus protection in studies. Only a small fraction of the vaccine produced for polio eradication would be enough to carry out the necessary studies, they argue.

Training for the innate immune system

The phenomenon of the protective non-specific effects of live vaccines has long been researched. They therefore strengthen the so-called innate immune system. The immunologist Mihai Netea did it in MIRROR As stated once before: “Plants and invertebrates that only have an innate immune system adapt after one infection and react better at the next one.” This happens through “very old mechanisms” such as epigenetic changes. “In principle, vaccinations simulate very slight infections and can therefore trigger these helpful non-specific effects – without the risk of a real disease.”

Researchers are now hoping to use this effect against Sars-CoV-2, while a specific vaccine against the virus has yet to be developed. Initial studies with Sars CoV-2 vaccines are ongoing in many countries, but optimistic estimates mean that it will still take almost a year and a half before a vaccine is ready for the market – it could also take significantly longer.

Using an old vaccine that has already gone through all the necessary safety studies and is well known for decades of use could be implemented much faster.

New tuberculosis vaccine tested against the corona virus

Not only is polio swallowing a possible candidate, but BCG vaccination against tuberculosis could also offer protection against the novel Corona virus to lend. BCG already knows that the vaccine is generally better able to arm the immune system against infections.

Because BCG vaccination was compulsory in the GDR until the end of it, more people received the vaccine there than in the West: does this contribute to the fact that the eastern German states have so far been less affected by the coronavirus epidemic?

So far, this question has not been answered clearly. “There are indications that tuberculosis protection from BCG vaccination lasts about 20 years,” says Christoph Schindler from the Hannover Medical School. It is not known exactly whether the vaccine effect lasts longer.

Schindler and his colleagues are currently testing a modified BCG vaccine, called VPM 1002, in two phase III clinical studies: 1,000 people working in the healthcare sector (doctors, nurses, medical and technical specialists with patient contact) and 2,000 people between the ages of 60 and 80 years of age receive vaccination or a placebo. Recruitment of the test subjects is going well, says Schindler.

BCG bridging vaccination

The BCG vaccine contains a bacterium, the Bacillus Calmette-Guérin, which is closely related to the tuberculosis pathogen and has been weakened for the vaccination. This bacterium has been genetically modified for the new vaccine VPM 1002, so that the vaccination produces a better and more targeted immune response than the conventional vaccine and less frequently causes undesirable side effects. The vaccination has already been tested in several clinical studies.

As soon as the last subject was recorded, the participants should be accompanied for 240 days. The team follows the thesis that the vaccine can not only offer some protection against the coronavirus, but could generally protect against respiratory infections. That is why they want to run their study on the next flu season in the coming winter. They expect results next year.

Schindler sees vaccination as a bridge technology: it could help until a specific vaccine against Sars-CoV-2 is developed.

In their article in “Science”, the researchers led by Konstantin Chumakov also point out that protection from live vaccines such as BCG or polio swallowing can even have an advantage over targeted vaccination: While Sars-CoV-2 could mutate in such a way that If a specific vaccination no longer provides effective protection, the non-specific protection remains in such a case. “If it turns out that the method is effective with Covid-19, an emergency vaccination with live vaccines could also serve as a first protection for other new pathogens,” they write.



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