The main concern is to weaken the response of the Omicron variant vaccines is due to the appearance of 32 mutations in the spike protein. To reduce the risks of creating new dangerous variants, the researchers propose to increase the production of vaccines and their coverage, especially in developing countries.
By Jennifer Juno, Senior Research Fellow, Peter Doherty Institute for Infection and Immunity and Adam Wheatley, Senior Research Fellow, Department of Microbiology and Immunology, University of Melbourne
The emergence of the omicron version of the corona virus SARS-CoV-2 that causes COVID-19 has rekindled global discussions about the spread of vaccines, mutations of viruses, and immunity against new virus strains. There have been experts, such as the omicron explorers from South Africa who speculate that the emergence of a new strain may be the result of low levels of vaccine coverage in developing countries.
So how are new versions of viruses created? And what is the role of the vaccine? The connection is still unclear but here is what we know so far.
Viruses change naturally during replication
A virus is life in the simplest form, and essentially contains two main components: (1) a reproductive program (made of DNA or RNA as in the case of the corona), and (2) proteins that allow the virus to enter cells, take over its mechanisms and begin to multiply.
If the virus reaches the lungs, it replicates rapidly and forms millions of virus particles. Some of these viruses are inhaled and infect other hosts.
It is important to note that the process of RNA replication of the virus is imperfect. Eventually errors will accumulate in the virus database and cause what we call virus versions.
What are the variants of SARS-CoV-2 and why are some of them worrying?
When viruses are transmitted from one person to another, some of the new variants created by the previous host will be more successful at entering cells or replicating themselves than others. In these cases, the “appropriate” variants are more likely to take over and become the primary virus that replicates within a population.
During the plague the phenomenon occurred several times. The original SARS-CoV-2 virus that came out of Wuhan in 2019 was later replaced with a version called the D614G, followed by the alpha version and now, the Delta version. Whenever someone is infected with SARS-CoV-2, there is a chance that the virus will mutate to a more suitable version, which can spread later.
What is the effect of the change in the virus on the vaccines?
Our current vaccines are still very effective against SARS-CoV-2 versions, including the Delta strain. This is because the vaccines target the entire “spike” protein of the virus, which is a large protein with a relatively small number of changes across variants.
Several versions of SARS-CoV-2 (Beta, Gamma, Lambda, and Mu) have been reported in the past as vaccine-evading “slips.” This means that the immune system is unable to detect the variable virus as the original strain, which reduces the effectiveness of the vaccine.
To date, however, the global impact of vaccine-evading strains has been limited. For example, the beta version, which hung the highest level of immune escape, failed to compete with Delta in the real world.
Do low vaccination rates pose a risk for new versions of viruses?
For now, any link between vaccine coverage and newer versions of SARS-CoV-2 is unclear. There are two main factors that can lead to the development of new versions. First, low vaccine coverage may increase the risk of new versions by enabling intra-community transmission. In this case, high viral replication and human-to-human transmission provide ample opportunities for the virus to mutate.
Alternatively, as vaccination rates rise, the only viruses that can successfully infect humans will be versions that escape at least partially from the music the vaccines provide. This scenario may require ongoing global surveillance efforts and new vaccines to maintain long-term control of the virus, similar to influenza.
Either way, when it is almost certain that as long as -COVID-19 remains in the environment, we must expect new strains to continue to challenge health systems. We will need careful and active management to address this risk.
So where did the omicron variant come from?
Recent reports of a new and alarming version, Omicron, have lit a red light. The variant was discovered by impressive flooring efforts of South African scientists, Omicron contains 32 amazing changes in the spike protein alone and contains mutations that can increase transmission and evade vaccines, so there is a risk that Omicron may spread rapidly and reduce (but not eliminate) the effectiveness of current vaccines.
Vaccine coverage in South Africa is very low relative to the West. Some argue that global inequality in the supply of corona vaccines may be responsible for the appearance of omicron. However, the extensive mutations in the omicron are consistent with changing the virus over time, as it is replicated in a person with a compromised immune system. Such highly mutated variants have been documented in the past but generally have not been widely spread.
Global vaccine coverage is beneficial for all of us
Expanding global vaccine coverage by increasing supply, ensuring fair distribution and combating hesitation and misinformation remained critical.
High global vaccine coverage will limit overall viral evolution, protect vaccine-suppressed people and reduce the chances of spreading highly mutated viruses, all of which can directly or indirectly reduce the risk of new variants emerging.
Because the global community is now very connected, countries will find it difficult to maintain the security of their citizens in the face of epidemic threats without adopting a framework for greater international cooperation and coordination.
For an article on The Conversation website
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