Reuse old vaccines to boost innate immunity to COVID-19

The COVID-19 vaccine is currently the best defense against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its variants.However, a new outlook article published in the journal PNAS It suggests that stopping SARS-CoV-2 is not a panacea. Robert C. Gallo of the University of Maryland School of Medicine and colleagues at the Global Virus Network have proposed the administration of vaccines that boost innate immunity using already weakened viruses such as tuberculosis, measles, and polio.

Global immunization is needed to end the pandemic, but some countries cannot accelerate immunization campaigns like some Western countries do. Vaccination will begin in 2022 in some countries, at risk of developing more deadly and potentially immune-avoidant mutants.

By strengthening the body’s first line of defense, researchers claim it helps stop new pathogens before they spread. Older vaccines that stimulate innate immunity can slow the spread of the virus, give scientists more time to develop a particular vaccine, and prevent another pandemic.

“The widespread protection induced by LAV is not compromised by potential antigenic drift (antigenic escape) that can make the virus resistant to certain vaccines. LAV” bends the pandemic curve. ” It provides an essential tool for, avoids the depletion of public health resources, and has the potential to prevent unnecessary deaths.

Discussion to strengthen innate immunity

Innate immunity is the body’s immediate response to external pathogens. Innate immunity takes only a few minutes, unlike acquired immunity, which takes days or hours to develop T cells and antibodies. Previous studies have shown that innate immunity alone was sufficient to overcome pathogens and infections.

This figure shows how a healthy innate immune system protects most people in the population from infection. With an already robust or trained innate immune system, the overwhelming majority of people infected with new pathogens such as SARS-CoV-2 eradicate infection early in the asymptomatic or mildly symptomatic infection stage. can. Without prior exposure or vaccination (eg, using a messenger RNA vaccine), adaptive immunization takes days to weeks to initiate, is often suppressed in severe cases, and is self-permanent and detrimental hyperinflammation. Contributes to the reaction. The innate immune system is often ineffective due to age, certain comorbidities, immunosuppression, and genetic susceptibility.

Innate immunity lies in its widespread non-specific activation and ability to block multiple pathogens. In SARS-CoV-2, innate immunity is triggered by detecting the nucleotide sequence of viral RNA.

Researchers say that vaccine-induced innate immunity with influenza and HIV vaccines can last as long as adaptive immunity. Innate immunity also has natural memory to train the immune system to recognize foreign pathogens faster.

“In this article, during a pandemic (or epidemic), medicine can quickly harness the power of innate immunity to induce partial defense against the threat of new (such as SARS-CoV-2) or re-emerging infectious diseases. This is achieved by diversion of several established live attenuated vaccines (LAVs), which are powerful inducers of innate immunity. “

Researchers note that innate immunity can control SARS-CoV-2 based on the success of other prophylaxis. Coronavirus Such as SARS and MERS, which may correlate with a better clinical response.

Bat-derived coronaviruses are also associated with the “appropriate balance of innate immune response between resistance and resistance.” Bats have high expression of NK cells and IFN, suggesting that innate immunity is required to control SARS-CoV-2.

Older vaccines show partial benefit to COVID-19

Distrust of COVID-19 vaccine storage and rapid vaccine development Herd immunity.. You can avoid these problems by using old vaccines that have been trusted and widely used for many years.

Old live attenuated vaccines also help because they target specific viruses of interest and provide broad protection against other pathogens. Studies over the last decade have shown that the non-specific effects of these vaccines are increased by booster shots. For example, some animal studies have shown that the influenza H3N2 vaccine is also protected from respiratory syncytial virus by increasing cytokine levels and white blood cells.

Epigenetic mechanisms induced by LAV in spontaneous immune cells and their progenitor cells: post-vaccination histone methylation and acetylation “mark” genes required for host defense and long-term chromatin structure It causes change and subsequent stimulation results in stronger expression.

Stronger protection against SARS-CoV-2 was observed among healthcare professionals with a history of Calmette-Guerlain vaccination.Another study confirmed these findings with less observation COVID19 Symptoms The severity of people receiving the Calmette-Guerlain vaccine is not very high.

There are economic benefits to using older vaccines to stimulate innate immunity. Some COVID-19 vaccines available are expensive to refrigerate and implement. It is also more cost effective and protective to provide a live attenuated vaccine as booster immunity for additional protection rather than waiting for a second dose for 4 weeks.

“Even LAV, which is only 50% effective, can prevent several primary infections per 1,000 vaccinated people than a vaccination schedule that provides only the COVID-19 vaccine. A Reff of 2 will prevent it. The total number of infections can be double the number of primary infections prevented, and even after 4-5 weeks, LAV can only benefit the COVID-19 vaccine. “