What’s next after omicron?

| February 3, 2022
  • How soon should we expect a new variant of concern to emerge?

“Newer variants are inevitable when it involves RNA viruses. Generally, the RNA virus replication machinery is error-prone and each time the virus infection passes from person to person, given time, the possibility of newer variants is always high.

Why do we get variants? Every time the virus reproduces inside someone there’s a chance of it mutating and a new variant emerging. This is a numbers game. It’s a random process, a bit like rolling dice. The more you roll, the greater the chance of new variants appearing. It’s basically a ticking timebomb.

The main way to stop variants is equal global vaccination. The emergence of Omicron reminds us of how important that goal remains. We must get vaccines to these people as quickly as possible, especially in countries that are behind in their vaccination rate, both to help the people there who are vulnerable but also to stop new variants from emerging.

Let us not forget that in South Africa, where just close to 30 per cent of people are fully vaccinated, the variant has begun to spread rapidly. A number of factors could be contributing to the rising caseload, including the nation’s low vaccination rate. Vaccine equity is a global problem! If we don’t address this quickly enough, our exit from the pandemic will be set back, possibly for months/years on end.

Another problem we are facing is that currently available vaccines based on the ancestral strain are less effective with the current variant of concerns, especially the rapidly circulating Omicron variant. While booster doses seem to increase protection to a certain extent, it is not viable in the long run.

A variant specific vaccine (booster dose) is absolutely pertinent going forward in controlling transmission and the disease itself. While Pfizer and Moderna have indicated that we could be getting the variant-specific booster doses as early as March 2022, there is a huge problem in terms of logistics and procurements for many countries, especially among low-income nations.”

  • Can we predict if it is likely to be more, or less transmissible and/or more, or less deadly? 

“It is extremely hard to predict whether future variants of concern will be more or less likely to be deadly. The subject of mutation is always intriguing especially when it involves viruses. Generally, it all comes down to probability.

Viruses are continuously changing as a result of genetic selection. They undergo subtle genetic changes through mutation and major genetic changes through recombination. Mutation occurs when an error is incorporated in the viral genome, and with error-prone replication machinery, the chances of it happening are extremely high especially when it goes from one host to another.

RNA viruses have much higher mutation rates, perhaps one mutation per virus genome copy. Mutations can be deleterious, neutral, or occasionally favourable. Another factor which drives mutations is selection pressure to adapt to the hosts, i.e., overcoming the host immune defence system. Only mutations that do not interfere with essential virus functions can persist in a virus population.

One thing for sure is that, with gross inequality in terms of vaccines between countries, chances of mutants arising in an unvaccinated population is much higher especially from immunocompromised individuals who don’t usually mount sufficient immune response against pathogens/infection. This needs to be seriously addressed by every country fighting the pandemic since it is a global problem.”

  • How should we prepare for the next VOC? What scenarios should we be planning for?

“Despite the risks from Omicron and potentially the next Variant of Concern, the overall public health strategy used throughout the pandemic remains effective and is of utmost importance. We should not forget that already we have the ‘tools’ (e.g., masks, social distancing, etc.) to reduce the risk of becoming infected.

It should therefore be our main goal to slow down virus spread by adhering to the existing hygiene and speeding up the vaccination (which now has to include booster doses at all age groups) process. Current vaccines while shown to be less effective, have not been rendered completely ineffective. Until we have a variant-specific booster or a pan coronavirus vaccine, getting booster doses is the next best thing we can do.

Next, is disease surveillance. The first link in the disease surveillance chain is testing. Who is infected and where are they? Without accurate, timely testing, it can become impossible to curb the spread of a pathogen. We need to have a coordinated national testing plan in each country.

We have learned from experience that countries without an efficient testing plan allowed the virus to spread, unseen and unchecked, increasing the burden on hospitals and making other mitigation measures more difficult. Without accessible testing, the strategy that helped other countries (successful ones) break the chain of transmission — swiftly identifying people with the virus, isolating them and tracing their contacts — stood little chance.

The next vital link in the surveillance chain is routine, widespread genomic sequencing. This kind of surveillance helps experts keep tabs on how a pathogen is mutating and how new variants are spreading. This requires coordinated efforts between the private and government sectors in each country so that it can be done in an accurate and timely manner since time is an essential factor in curbing transmission.”

  • Is a universal COVID vaccine for all variants likely?

“A universal COVID-19 vaccine is definitely the way forward in the long run. To counter future coronavirus outbreaks, the global scientific and medical research community should focus a major effort now on three goals: characterising the range of coronavirus genetic diversity in multiple animal species; better understanding coronavirus disease pathogenesis in laboratory animal models and people; and applying this knowledge to the development of long-lasting, broadly protective coronavirus vaccines.

One such effort is the recent announcement from the US Army of the successful trials of a pan coronavirus vaccine, named SpFN, for Spike Ferritin Nanoparticle, which has shown promise in non-human primate trials. Early human trials are currently underway with results expected soon. The vaccine is designed on a new platform called “self-assembling protein nanoparticle.”

Unlike most currently available vaccines, which use mRNA to trigger the immune system, this shot would work by injecting a molecule that looks a little like a 24-faced football. Each face of the “ball” would carry a bit of the spike protein that can trigger the body to mount a protective immune response.

This allows scientists to attach the spikes of multiple coronavirus strains on different faces of the “ball,” so the body could protect against several variants at once, instead of having to take a separate dose for each variant. According to a study published in the peer-reviewed journal Science Translational Medicine, SpFN protected non-human primates from disease caused by the original variant of the COVID-19 coronavirus. Two doses given 28 days apart also triggered strong immune responses against Alpha, Beta, Gamma, and Delta variants. This really looks promising!”