Upgrading to COVID-19 vaccines means currently receiving three or four doses of the same shot. The current amplifiers are the same formulas as the first shots based on the original strain of the coronavirus, which appeared in late 2019. They still protect against severe COVID-19, permitted hospitalization, and death.
But as immunity declines over time and new, infectious SARS-CoV-2 variants emerge, the world needs a long-term boost strategy.
I am an immunologist who studies immunity against viruses. I was part of the teams that helped develop Moderna and Johnson and Johnson SARS-CoV-2 vaccines and AstraZeneca monoclonal antibody therapy with Eli Lilly.
I am often or seldom asked if I think people may need a COVID-19 amplifier shot in the future. No one has a crystal ball and cannot see which SARS-CoV-2 variant will come next or how well future variants will be better at avoiding vaccine immunity. But looking at other respiratory viral enemies that have plagued mankind for some time may suggest the future.
The flu virus is an example. It is endemic in humans, i.e. it has not disappeared and continues to create recurring seasonal waves of infection among the population. Every year, officials try to predict the best formula for influenza vaccination to reduce the risk of serious illness.
While SARS-CoV-2 continues to evolve and may become endemic, humans may need periodic intensifying shots in the near future. I think scientists need to update the COVID-19 vaccine to get new options against the flu.
Prediction of influenza, based on careful observation
Influenza Surveillance SARS-CoV-2 offers a model of how to monitor over time. Influenza viruses caused several pandemics, including the 1918 pandemic that killed an estimated 50 million people worldwide. Every year there are seasonal outbreaks of influenza, and every year the authorities encourage the population to be vaccinated against influenza.
Each year, health agencies, including the World Health Organization’s Global Influenza Control and Response System, rely on strain strains in the Southern Hemisphere to accurately predict which of them will be most prevalent during the Northern Hemisphere flu outbreak. Then large-scale vaccine production will begin on the basis of selected influenza strains.
In some flu seasons, the vaccine does not match the strains of the most common virus. In those years, bullets were not good at preventing serious illness. While this prediction process is not ideal, the field of influenza vaccines has benefited from strong viral surveillance systems and international efforts developed by public health agencies.
Although data on influenza and SARS-CoV-2 viruses are different, I think the COVID-19 field should consider adopting similar surveillance systems in the long run. Being around which strains will help researchers update the SARS-CoV-2 vaccine to match modern variants of the coronavirus.
How SARS-CoV-2 has evolved so far
SARS-CoV-2 faces an evolutionary abyss as it multiplies and spreads from person to person. The virus must maintain its ability to enter human cells with the help of its spik protein, while avoiding vaccine immunity. Vaccines are designed to recognize a specific protein in your body, so the more you change it, the more likely it is that the vaccine will be ineffective against the new variant.
Despite these challenges, SARS-CoV-2 and its variants have evolved to be more contagious and to better avoid human immune reactions. During the COVID-19 pandemic, a new variant of anxiety, SARS-CoV-2, emerged and was dominated by the transmission of a series of infectious waves every four to seven months.
Almost like the clock mechanism, the D614G variant appeared in the spring of 2020 and surpassed the SARS-CoV-2 epidemic strain. In late 2020 and early 2021, the alpha variant emerged and transmission dominated. By mid-2021, the delta variant had crossed the alpha, and then dominated until the end of 2021, when it was replaced by the omicron variant.
There is no reason to think that this trend will not continue. In the coming months, the world may see a predominance of various omicron subvariants. And a new variant may emerge from the non-dominant pool of SARS-CoV-2, which is how the omicron itself came into being.
Current boosters are additional doses of vaccines based on the release of the long-extinct strain of SARS-CoV-2 virus. Coronavirus variants have changed significantly from the original virus, which is not good for continuing the effectiveness of the vaccine. The idea of a special vaccine every year, like the flu vaccine, sounds appealing. The problem is that scientists have not been able to predict with certainty what the next version of SARS-CoV-2 will look like.
Planning for the future
Yes, the SARS-CoV-2 variants that dominate the coming fall and winter may look different from the currently circulating omicron subvariants. However, the updated amplifier, which is more similar to modern omicron subvariants, offers better protection in the future for human immunity from the first vaccines. This may require a less frequent increase – at least if the omicron subline continues to dominate.
The Food and Drug Administration will meet in the coming weeks to decide what fall amplifiers should be for manufacturers. Vaccine developers, such as Modernna, are currently testing stronger candidates in humans and assessing the immune response to emerging variants. The test results determine what to use in the fall or winter.
Another possibility is to change the vaccine enhancement strategy to include universal coronavirus vaccine methods that seem promising in animal studies. Researchers are working on a universal vaccine that will be effective against several strains.
Some focus on chemical reactions that combine parts of different coronaviruses into a single vaccine to boost the immune system. Others are experimenting with nanoparticle vaccines, which allow the immune system to target the most vulnerable areas of the coronavirus.
These strategies have been shown to eliminate SARS-CoV-2 variants that are difficult to stop in laboratory experiments. They are also working against the SARS virus, which caused an epidemic in animals in the early 2000s, as well as zoonotic coronaviruses from bats, which jumped on humans and caused future outbreaks of SARS-CoV-3.
Science has provided several safe and effective vaccines that severely reduce the risk of COVID-19. Redesigning universal-based vaccines or updated enhancement strategies will help save us from the COVID-19 pandemic.
David R. Martinez is a postdoctoral fellow in epidemiology at the University of North Carolina at Chapel Hill.
This article was reprinted from The Conversation magazine under a Creative Commons license. Read the original article.