The race against new variants continues

Honestly, how many of us in Bangladesh were aware of terms like “anti-vaxxers” or “science deniers” before the pandemic? The recent drama surrounding the unvaccinated tennis star Novak Djokovic being deported from Australia is a case in point.

The celebrity was spotted earlier attending functions and photo sessions even after testing positive for Covid. This kind of reckless behaviour is not uncommon in the West, where public safety is compromised by competing concerns over individual rights. Fortunately for us, collective well-being usually takes precedence. Our record — even through years when we were far less resourced than today — on immunization programs was in a sense re-enacted in the Covid-19 vaccination drive.

With the onset of the Omicron variant, a large portion of our population is just starting to subscribe for the booster shot. When countries like Israel are jabbing their people with the fourth shot, only 33% of our population are currently fully vaccinated. As we scramble to get everyone vaccinated, Omicron with an Ro (the reproduction number) of 10 will probably spare no one, at least in the urban places. Despite the rapid innovation of vaccines, the world continues to be in a race against emerging variants.

How do variants come into being?

Immunocompromised patients are thought to be the main source of variants. Sars-Cov2 is an RNA virus that hijacks the human cells once it enters and starts replicating itself without a “proof-reading” step. When this happens, the human body’s immune system tries to eliminate the virus, but the virus keeps replicating and evolving. Scientists believe that when the virus tends to linger longer in immunocompromised patients, it mutates enough to emerge as a new variant.

The virus remained detectable in one patient in South Africa for 216 days. The alpha variant is thought to have arisen from a persistent infection in the UK.

This is another reason why people with cancer, organ transplant, unmanaged diabetes or autoimmune diseases need to be protected. Their well-being is important not only for themselves but also to reduce chances of engendering new variants. Sufficiently changed or virulent new variants can potentially make the existing vaccines redundant.

The other theory is that a new variant is a product of reverse zoonosis. So, from human to animal, and then back to humans. Chinese researchers claim that a progenitor of Omicron jumped from humans to mice, mutated to a new variant, then jumped back to humans. This is why it is so important to learn who the patient zero was in Wuhan, how he/she caught it, whether it jumped species, bat-to-pangolin-to-humans, or whether it escaped from a lab.

Is Omicron an indication of a switch from pandemic to endemic?

The lessened severity of Omicron variant gives hope that the pandemic may switch to endemic. “Covid Zero” situation is deemed impossible since the virus has been detected in the domestic poultry, horseshoe bats, and mice by researchers in Imperial College of London. As the variant has multiple reservoirs of hosts and given the ability to jump species, it is possible for it to evolve in any direction.

Historically, there have been incidences where viruses have gone extinct. SARS and Swine flu has almost disappeared by a combination of contact-tracing and the mutations of the virus itself. Flu viruses evolve but the ones that existed 120 years ago has gone extinct. But then there are the seasonal ones, the HIV and Ebola viruses that continuously mutate and makes development of a generic vaccine almost impossible.

How fast does Omicron spread and what are the common symptoms?

Omicron virus multiplies very rapidly in the upper respiratory tract, the incubation period is only three days, and the highest viral shedding happens between the third and sixth day but may continue even after nine days. Since one person can infect ten people with brief exposure, contact tracing is very difficult. Even though 80% people will have mild to asymptomatic symptoms, the high transmissibility can overwhelm the healthcare system and people with co-morbidities like diabetes and high blood pressure remain at risk.

Common symptoms for the vaccinated people are nasal congestion, headache, body ache, cough, sneezing, sore throat, fatigue, and low-grade fever. Unvaccinated children and younger people may get a day of high fever of around 102 degrees Fahrenheit, followed by a short bout of cough and cold. In the majority of cases the symptoms resolve quickly and 70% do not require hospital care.

Omicron struggles to affect the deeper lung cells, which makes it a less dangerous variant compared to Delta which had an Ro of 5 and the ancestral variant with an Ro of 2 to 3. It is uncommon to develop loss of smell and taste with Omicron. It is also noted that many infected cases arriving at the hospitals are not struggling to breathe and the oxygen saturation is also not dangerously low.

So many breakthrough cases, are the vaccines still helping?

Yes. Vaccine is protecting us from hospitalization, the severity of the disease, and death. Omicron has 59 mutations in total, 36 of these are in the spike protein and looks very different from the ancestral Wuhan strain.Recent studies by the US Centers for Disease Control Suggest that a third booster shot, particularly with the Pfizer or Moderna vaccines gives solid protection against Omicron. It is highly recommended for people whose second shot was taken over six months ago.

Scientists are relying on the scale, severity and the long Covid symptoms of the breakthrough infections from Omicron before a tweak in the vaccine is recommended. Studies show that even if the antibodies fail to recognize the spike protein of the new variant, the T-cells respond to the whole of the spike protein and generate a robust immunity.

Pfizer and Moderna have stated that they can produce vaccines specific to omicron within 100 days.The experts do not recommend such tweaks yet as vaccines still give cross immunity and they want to avoid the risk of creating a two-tier system, where poorer countries are stuck with out-of-date vaccines.

Is there any new recommendation?

The guidelines are the same- masking up, social distancing, vaccination, and ventilation. The fatigue of living like this for two years, a better understanding of the infection, less severity of the disease, new drugs and vaccination have brought the guards down in people. The transmissibility with Omicron is such that we may see the peak of the wave soon followed by a sharp decline as well, since the virus will have infected everyone rapidly. South Africa and the UK claim to have passed their peak already.

Omicron is already a distant relative of the original Wuhan strain. We can only hope that SARS- COV2 virus eventually joins the other four common cold corona viruses and not mutates to another virulent variant. It will be necessary to produce vaccines tailored to the new strain or switch the vaccine strategy towards multivalent formulations that cover multiple strains, just like the seasonal flu vaccine.

“Vaccines save lives”– is a self-evident truth ingrained in the Bangladeshi mindset and the government did not have to provide incentives to people to get inoculated. We need to utilize the country lag of three months and ramp up vaccination as much as possible because this is the only measure that reduces death and hospitalization even if one is a breakthrough case.

 

Dr. Maliha Mannan Ahmed is the Founder and Executive Director of Organikare. She has an MBBS, MBA, and a Master’s in Health Care Leadership.

Source of Dhaka Tribune