Breeding Grounds’ for New COVID-19 Variants

By: Dr Magdy Badran

The world has entered a dangerous new phase of the pandemic, as the coronavirus fourth wave creates fertile breeding grounds for more infectious and potentially vaccine-resistant new variants. The variants are pummelling unvaccinated people. Sixteen months after the novel coronavirus shut down much of the world, the pandemic is still raging. If we have large outbreaks, it does become a breeding ground for potentially more variants.

Lifting COVID Restrictions is Risky

Removal of COVID restrictions will do away with social distancing requirements, allow businesses to re-open to full capacity and remove legal mask mandates. This decision comes, however in some countries, amidst soaring infections rates in the country, driven by the delta variant.

In most areas of England, the rate of new coronavirus cases is back at levels last seen during the winter, while hospital patient numbers have risen to levels last seen in April. Allowing more infections to occur, especially in people not fully vaccinated, runs the risk of potentially dangerous variants emerging. However, it’s not easy to predict when and where the next variant will emerge. Many countries around the world have high levels of infection as well as circulating variants that we don’t yet fully understand.

There’s, therefore, a need for ongoing surveillance of variants around the world. If a new variant of concern were to emerge and spread rapidly, especially one capable of evading vaccine protection or causing more severe disease, then the governments may have to consider reintroducing some public health measures. This could include lockdown. If the pandemic has taught us anything, it’s the need to be flexible and to act fast against this evolving virus.

Children

Relaxing control measures while the majority of the world’s population remains unvaccinated risks the evolution of more transmissible, more virulent variants. These variants may be more dangerous for children and certain vulnerable groups, such as transplant patients with compromised immune systems, they argue. They may also escape the protection afforded by existing vaccines.

Even in countries where vaccination has reduced the numbers of hospitalizations and deaths, high case numbers and large numbers of unvaccinated inpiduals provide a mixing vessel in which new variants can emerge.

Increasingly Transmissible Variants

During the course of the pandemic, a succession of more transmissible variants have become the dominant strains within populations. When a virus is widely circulating in a population and causing many infections, the likelihood of the virus mutating increases. The more opportunities a virus has to spread, the more it replicates – and the more opportunities it has to undergo changes.

Most viral mutations have little to no impact on the virus’s ability to cause infections and disease. But depending on where the changes are located in the virus’s genetic material, they may affect a virus’s properties, such as transmission (for example, it may spread more or less easily) or severity (for example, it may cause more or less severe disease).

Because these remain high, this allows for continued evolution of the virus, and that comes at a risk, including the evolution of more virulent variants, or variants that can escape the vaccine.

We recommend that control measures such as the mandatory wearing of face masks in indoor public places remain in place until most of the population has received a vaccine.

Delta is Not The Last Variant

Viruses create variants to try to escape immunity, either vaccine-induced or natural that comes after being infected. Delta, or B.1.617.2, was first identified in India in Dec. 2020.The Delta variant of COVID-19 continues to spread faster , now it is the dominant strain worldwide and 132 countries globally have reported detection of the Delta variant.

Data indicate that Delta is 40-60% more transmissible than Alpha and almost twice as transmissible as the original Wuhan strain of SARS-CoV-2. Furthermore, significantly more viral particles have been found in the airways of patients infected with the Delta variant.

A Chinese study reported that viral loads in Delta infections were ~1,000 times higher than those in infections caused by other variants. In response this information, the World Health Organization (WHO) regards Delta as “the fastest and fittest” variant so far.

The CDC warned the delta variant sweeping across the USA is as contagious as chickenpox, has a longer transmission window than the original Covid-19 strain and may make older people sicker. A confidential CDC document said delta is more transmissible than the common cold, the 1918 Spanish flu, smallpox, Ebola, MERS and SARS.

Based on what has happened so far and the huge amount of virus transmission worldwide, it is unlikely that this Delta will be the last wave. We should be proactive in keeping transmission rates low with all means available and anticipate new waves better able to transmit through unvaccinated and partially immune populations.

Why do SARS-CoV-2 Mutate?

Viruses mutate as they replicate. Replication requires that the virus’s genetic information is copied. But this copying is not accurate. It produces mistakes such as substitutions, deletions or sometimes insertions of amino acids – the building blocks of proteins. These changes are called mutations.

Some of these mutations are advantageous to the virus allowing it to survive in new hosts or new environments. A new environment can mean evading an immune response mounted by the host or a therapeutic drug. The SARS-CoV-2 virus mutates just like other viruses. Mutations in the coronavirus are common; to date there have been about 4000 mutations in its spike protein alone.

The initial genome of COVID-19, consisting of 30,000 letters, was revealed in January 2020.Since, then mutations - consisting of a letter change in the genome - have been reported all over the world. More than 20,260 of these changes are now found in the 100,000 Sars-CoV-2 sequenced to date. But any two viruses from any two patients anywhere in the world differ on average by only 10 letters, meaning Sars-CoV-2 is part of a single clonal lineage.

Mutations in viruses are notable only when they change an important characteristic of the virus such as its ability to infect different hosts, rate of transmission, ability to evade the host’s immune system, vaccines, therapeutics and diagnostics, cause pathology or disease severity.

Effect of Variants on Vaccines

The COVID-19 vaccines that are currently in development or have been approved are expected to provide at least some protection against new virus variants because these vaccines elicit a broad immune response involving a range of antibodies and cells. Therefore, changes or mutations in the virus should not make vaccines completely ineffective. In the event that any of these vaccines prove to be less effective against one or more variants, it will be possible to change the composition of the vaccines to protect against these variants.

While we are learning more, we need to do everything possible to stop the spread of the virus in order to prevent mutations that may reduce the efficacy of existing vaccines. In addition, manufacturers and the programmes using the vaccines may have to adjust to the evolution of the COVID-19 virus: for example, vaccines may need to incorporate more than one strain when in development, booster shots may be required, and other vaccine changes may be needed.

Trials must also be designed and maintained to allow any changes in efficacy to be assessed, and must be of sufficient scale and persity to enable clear interpretation of results. Studies of the impact of vaccines as they are deployed are also essential in order to understand their impact.