The rapid spread of the omicron variant of Covid-19 is forcing governments worldwide to impose strict containment measures, but there are some glimmers of hope in the data currently available, according to experts.
While it is still too early to know for sure the severity of the variant, studies so far indicate that the damage it causes is likely to be at worst akin to previous variants, and possibly milder.
Recent data from South Africa — where the strain first emerged — along with a study from Hong Kong and developments from vaccine manufacturers, seem to point to some potential elements of good news amid the overarching dangers. And hospitalization and death rates are so far significantly lower than with previous variants.
“We have anti-viral drugs which will work against omicron, vaccines that work to an extent and can be improved, and lateral flow tests which allow us to check our infection status in real time,” Lawrence Young, virologist and professor of oncology at the University of Warwick, told CNBC on Tuesday.
Still, medical experts agree that the higher transmissibility of the virus poses a severe threat to health care systems even if symptoms are milder, because the sheer volume of infections will likely lead to more people needing hospital care.
The World Health Organization has warned that omicron infections are doubling every 1.5 to 3 days in areas with community transmission, and the variant has now been detected in at least 89 countries.
Danny Altmann, professor of immunology at Imperial College London, told CNBC via email on Tuesday that even if omicron does prove to be “milder” than other strains, the potential caseload could double or triple the number of people needing hospitalization in the U.K., where the virus is currently rampant — with particular risk to the unvaccinated.
1. Promising T cell response
Young, the virologist at the University of Warwick, described findings on the body’s response to omicron, highlighting a particular reaction that bodes well for evading severe symptoms of the virus.
“It’s important to note that while laboratory data shows that the spike protein of the omicron variant is relatively resistant to the virus blocking antibodies induced by vaccination or natural infection, the T cell response is likely to be highly conserved,” he said.
This is because it targets regions of the spike protein that are highly consistent between the omicron variant and the original Wuhan virus, on which current vaccines are based, Young explained.
The conservation of the T cell response once the virus has broken through the vaccine’s outer defenses and entered the body would lessen the risk of the host developing severe symptoms.
2. Lower rate of infection in lungs
A study from the University of Hong Kong, led by Dr. Michael Chan Chi-wai, found that omicron transmits faster and more effectively than the previously dominant delta strain in the human bronchus.
However the study, which is currently under peer review, also discovered that omicron infection in the lungs is significantly lower, indicating that it may have a less severe impact on those who get infected.
In other words, it is more infectious, but less likely to be able to attack vulnerable parts of our anatomies.
But Dr. Chan also noted that simply by infecting many more people, a highly infectious virus “may cause more severe disease and death even though the virus itself may be less pathogenic.”
“Therefore, taken together with our recent studies showing that the Omicron variant can partially escape immunity from vaccines and past infection, the overall threat from Omicron variant is likely to be very significant,” he added.
However, Young stressed that the findings from Hong Kong so far are “intriguing but very preliminary.”
3. Boosters work
Evidence has suggested that vaccinated people, particularly those who have received booster shots, are far less at risk of hospitalization or death from the new variant.
Some more promising news on this front came on Monday, when Moderna announced that its booster inoculation had shown itself to be effective against the omicron variant in laboratory testing.
Benjamin Cowling, professor at the School of Public Health at the University of Hong Kong, told CNBC on Monday that data thus far indicates that the omicron variant causes around the same disease severity as delta and other previous variants in unvaccinated patients or those who have never been infected.
“If you have been vaccinated, if you have had an infection before, you have got some protection, particularly against severe disease, and that means that omicron in reality looks milder. It looks like a milder infection because of the immunity that we have built up, not because the virus is particularly different in terms of its natural innate severity,” he said.
Cowling explained that vaccines offer two lines of defense, firstly through antibodies to protect against infection and secondly through T-cells which protect against severe disease in the event of a breakthrough infection.
“If we get that third dose, the booster, it strengthens that outer line of defense and we are back to where we were maybe six months ago, where having three doses does give us those two lines of defense back.”
However, Young emphasized that while the booster data so far is promising in its effectiveness against severe symptoms, it will not necessarily negate the potential for the variant to overburden health systems.
“The latest preliminary modelling indicates that a booster jab could provide around 85% protection against severe disease from omicron – but that means that 15% of boosted individuals won’t be fully protected, and added to those who are unvaccinated or not boosted, this is a huge number of vulnerable individuals,” he said.
4. Lower hospitalizations in South Africa
This suggestion has been echoed in South Africa, where the virus was first identified by scientists in late November, though it was most likely already present in other countries around the world at that time.
The country experienced a rapid rise in cases which appears to have since peaked in the hotspot Gauteng region around three weeks after first detection.
Despite the surge in cases, the rolling average of daily deaths remained low, marking a sharp divergence from previous waves and variants.
Health minister Joe Phaahla said in a press conference last week that just 1.7% of omicron cases were being hospitalized, compared to 19% when the delta variant emerged.
However, Phaahla also expressed concern about declining vaccination rates, suggesting that it may not just be that omicron is less virulent, but that vaccinations and natural immunity are adding to the protection from severe cases among the infected.
Young told CNBC that extrapolating from the experience in South Africa is “complicated by the younger average age of the infected individuals, their immune status and the fact that it’s summer in South Africa, and this may be influencing the spread of omicron.”
5. Antiviral drug developments
Another possible green shoot in the effort to constrain the impact of Covid has been advances in antiviral drug developments aimed at high-risk members of the population, such as the immunosuppressed or cancer patients.
Pfizer announced last week that its Paxlovid antiviral treatment was shown in second-stage trials to cut the risk of hospitalization or death in high-risk patients by 89% if administered within three days of symptom onset, and 88% within five days.
The U.K.’s medicines regulator also recently authorized the use of Xevudy (sotrovimab), a monoclonal antibody made by GlaxoSmithKline and Vir Biotechnology, and Lagevrio (molnupiravir), made by Ridgeback Biotherapeutics and Merck Sharp & Dohme.
On Wednesday, the U.K. government confirmed that it had ordered an additional 2.5 million courses of Paxlovid and 1.75 million of Lagevrio for delivery over the course of 2022.
Hospital capacity at risk and unvaccinated still highly vulnerable
Altmann, the immunology professor at Imperial College London, warned against taking the current data at hand as reason to relinquish caution.
A crucial vulnerability, he and other professionals stress, remains the unvaccinated. Hospitalizations will be skewed towards the portion of the population who are unvaccinated or have had only one vaccine dose.
Looking at the U.K. specifically, he said: “At a time when NHS (National Health Service) are A) massively depleted by omicron and B) massively stretched and fatigued after two thankless years on the frontline, this would be untenable,” he said, adding that there were “no green shoots yet.”