Scientists are working hard to develop a vaccine as the global outbreak of the new crown pneumonia continues, but even if it is “accelerated”, a vaccine will still have to wait 12 to 18 months. Recently, a new discovery suggests that a defense against the new coronavirus infection may be at hand.
According to a report from Russia Today, researchers from the Johns Hopkins Bloomberg School of Public Health published a paper on the medRxiv preprinted paper platform on the 6th, titled “Differences in New Coronary Pneumonia Attributable Mortality and BCG Use by Countries” , the paper said that the century-old Bacille Calmette-Guérin (BCG) vaccine used to prevent tuberculosis appears to have a protective effect against new coronavirus infection.
↑ Screenshot of the paper
The study could also explain why, on the Iberian Peninsula, nearly 11,000 people in Spain had died of the new coronavirus as of March 29, compared with 209 in neighbouring Portugal. Such a huge difference may be precisely because Portugal has a universal BCG vaccination program, while Spain does not.
At present, the conclusions of this study are based on statistical data, and the final answer needs to be verified by further clinical trials. So far, scientific teams in at least four countries have begun to adjust the tuberculosis vaccine to fight the new crown virus more quickly, so that we may not have to wait 12-18 months before we have a vaccine against the new crown virus.
What is BCG?
According to Russia Today, Bacillus Calmette Guerin (also known as BCG) was invented a century ago and is commonly used to prevent tuberculosis (TB). It contains a weakened form of Mycobacterium bovis, a close relative of Mycobacterium tuberculosis that causes tuberculosis.
↑ In 1931, the BCG vaccine ampoule developed by the Pasteur Institute in Paris. According to The New York Times
Often a vaccine elicits an immune response against a specific pathogen, such as antibodies that bind and neutralize one virus but not other types of viruses. And BCG works by boosting immune system cells in the bone marrow, which are then released to strengthen the immune system’s innate mechanisms, capable of responding to a variety of pathogens.
Experts say the vaccine appears to train the immune system to recognize and respond to a variety of infections, including viruses, bacteria and parasites, according to The New York Times. So BCG not only helps prevent tuberculosis, it also helps prevent a variety of other diseases. It is also used to treat measles, malaria, bladder cancer, and even to reduce respiratory infections in the elderly.
A study of older adults found that continuous BCG vaccination reduced the incidence of acute upper respiratory tract infections. A recent assessment by the World Health Organization also concluded that BCG has beneficial off-target effects and recommended more vaccine trials for a wider range of infections.
Therefore, the general protective effect of BCG has prompted scientists to investigate whether it is also suitable for pneumonia caused by the new coronavirus that is spreading around the world.
Countries with widespread BCG vaccination have nearly 10 times lower rates of COVID-19 infection and mortality
“We found that countries without a universal BCG vaccination policy (Italy, the Netherlands, the US) were more severely affected by Covid-19 infection than countries with a universal and long-term BCG vaccination policy.” In a preprint of the paper published on medRxiv , researchers at the Johns Hopkins Bloomberg School of Public Health found that countries with widespread BCG vaccination programs had nearly 10 times lower COVID-19 mortality rates than countries that did not.
↑Schematic diagram of the global BCG vaccination policy.Figure according to European News
Researchers from the Johns Hopkins Bloomberg School of Public Health pooled and analyzed publicly available data from 178 countries, of which 131 have BCG immunization programs, 21 do not, and 26 are unknown.
Next, the researchers adjusted for factors that could affect the findings, such as how wealthy a country is and the proportion of older adults in the population. In order to reduce the deviation of the different epidemic time curves experienced by countries, they calculated the number of days since the 100th confirmed case of new coronary pneumonia, aligning countries with more comparable time curves.
They then calculated the mortality rate per 1 million inhabitants in each country and compared them with confirmed cases and BCG vaccination programs.
“The association between BCG use and lower COVID-19 mortality remained detectable after adjusting for national economic conditions, the proportion of the elderly population, and the epidemiological trajectory of the worst-affected countries,” the paper reads.
For example, the United States and Italy, both wealthy developed countries, have never implemented a universal BCG vaccination program. Neither did Spain, but neighboring Portugal did. As of March 29, only 209 people in Portugal had died of new coronary pneumonia, far less than Spain’s nearly 11,000.
Judging from the current data of more than 15 days of the epidemic, the incidence of new coronary pneumonia in countries vaccinated with BCG is 38.4/million, while in countries without BCG, the incidence rate is 358.4/million. The death rate from Covid-19 in countries vaccinated against BCG was 4.28 per million, compared to 40 per million in countries without BCG.
It can be seen from the data comparison that in countries without BCG vaccination, the number of confirmed cases and deaths of new coronary pneumonia is about 10 times that of countries vaccinated with BCG. Dr Ashish Kamath, one of the paper’s co-authors, said, “We expected to see a protective effect from BCG, and the differences in morbidity and mortality between BCG and non-vaccinated countries were large ( almost 10 times) is quite surprising.”
↑ Large (almost 10-fold) differences in morbidity and mortality between BCG-vaccinated and non-BCG-vaccinated countries. According to “Daily Mail”
In addition, the average mortality rate varies widely according to the level of economic development of the country. The COVID-19 death rates in low-middle-income, upper-middle-income, and high-income countries were 0.4, 0.65, and 5.5, respectively. The researchers note that previous studies have shown that in low-income settings, countries are generally more likely to die from ARDs due to multiple sociodemographic and economic risk factors. So the fact that the death rate from Covid-19 is higher in richer countries is “counter-intuitive”.
However, it’s important to point out that this study is about correlation, not “causation.” The sheer number of qualifiers and caveats in this study means that factors other than BCG vaccination programmes may be influencing the number of confirmed cases and deaths in these countries. For example, Covid-19 is more dangerous for the over-65 age group, which is smaller in poorer countries.
“These findings warrant a more in-depth epidemiological review and prospective evaluation in individual randomized trials,” the researchers added.
At least 4 countries are testing the effectiveness of BCG against the new coronavirus
According to the British “Daily Mail” report, there are currently a number of trials evaluating the effectiveness of BCG in the fight against the new crown pneumonia epidemic.
This Monday, led by a research team from the Murdoch Children’s Research Institute in Melbourne, Australia, a clinical trial involving 4,000 healthcare workers has officially started. agent. Results are expected in about six months.
At the end of March, the research team of Netea, an infectious disease expert at the Radboud University Medical Center in the Netherlands, has also launched the first round of clinical trials of BCG to protect against new coronavirus infection. They are recruiting 1,000 medical staff from 8 Dutch hospitals.
According to the journal Science, the University of Essect in the United Kingdom has also announced that it will conduct trials in the elderly population, because the elderly are at higher risk of developing severe disease after contracting the virus.
A team of researchers at the Max Planck Institute for Infection Biology in Germany also announced last month that they would start trials of a gene-edited BCG vaccine in healthcare workers and the elderly, inspired by the Netea study. The vaccine, called VPM1002, is currently in Phase III clinical trials.
Dr. Dennis Fosterman, director of immunobiology at Massachusetts General Hospital, also revealed to the New York Times on the 4th that they are seeking funding to conduct clinical trials of BCG in medical staff in Boston, and the preliminary results will be as soon as 4 revealed within a month.
↑At least 4 countries are testing the effectiveness of BCG against the new coronavirus according to the “New York Times”
However, not everyone is convinced that the BCG vaccine will be successful against the new coronavirus. Columbia University endocrinologist Dr. Domenico Archili said the attempt to fight the new coronavirus with the BCG vaccine sounds “like a whimsical idea.” He noted that while BCG is a non-specific immune system booster, “we should be able to take a more targeted approach.”
Dr. Curtis, who was responsible for designing and conducting the trial in Melbourne, Australia, also said that while he believed that BCG was underappreciated, he also stressed that it was not a specific COVID-19 vaccine.
Whether BCG can protect against new coronavirus infection, perhaps we will find out in the next few months.
Red Star News reporter Wang Yalin Xu Huan
Edited by Peng Yi