Prof Salim Abdool Karim

With global excess death statistics
indicating that almost 17 million people have succumbed to Covid-19 in the past
two years rather than the official figure of around 5.2 million and a
resurgence of new infections in many countries, there are still many
uncertainties on how South Africa will be impacted when the expected 4th wave
hits in the coming months.

According to the South African COVID-19
Modelling Consortium’s latest predictions released this week, the 4th wave
could be less severe than the devastating second and third wave in terms of
hospitalisations and deaths due to vaccine coverage and protection from
previous exposure. However, these projections are based on the absence of a new
variant and continuing protection of existing vaccines.

But the Consortium warns that if a new
variant with a 25% relative reduction in protection from prior infection and vaccination
enters the country, hospital admissions could start to escalate again although vaccines
will continue to have an impact and may protect the most vulnerable from severe
illness.

“Smaller peaks in admissions do not
necessarily imply that future waves will have less impact on the health system
and healthcare workers. Whether or not the admissions will result in
overwhelmed hospitals and avoidable COVID-19 deaths also depends on how much
hospital capacity can continue to be made available,” the report warns.

Speaking at the KZNDHC Healthcare Institute’s
recent virtual 25th annual conference, Caprisa Director and government’s former
chief adviser on Covid-19, Prof Salim Abdool Karim emphasised
that the devastation caused by new variants in the previous two waves showed
how the virus’s ability to change itself was underestimated. In some countries,
particularly the UK and Russia, the sub-lineage of the highly transmissible and
infectious Delta variant, AY.4.2 or Delta Plus, is driving the resurgence
because of its ability to escape immunity and reduce the efficacy of current vaccines.
However, it is not yet clear if it is more transmissible than the original
Delta variant. But says Prof Karim, the potential spread of sub-lineages in South
Africa may be the harbinger of what we may see in the next wave.

In Columbia, a new variant called Mu has
been overtaking the Delta and Gamma variants. Prof Karim says although it has
not been detected in South Africa, it is carefully monitored because of
concerns about its ability to better escape neutralisation from vaccines than
any of the other existing variants.

“Our biggest concern is that the next
variant may have an increased risk of immune escape because we have seen how it
occurs in terms of the impact of clinical efficacy of Covid-19,” prof Karim
warned.

“Essentially, we are vaccinating people
because we are hoping it will keep variants at bay, but this has not yet been proven.
We will need to know what the clinical and vaccine implications are for each variant
to establish how protected people are to determine how restriction should be
eased,” Prof Karim said.

No vaccine will ever be 100% effective against
infection, Prof Karim stressed. People will get infected and reinfected despite
being vaccinated. However, the current resurgence in the UK has shown that
despite it spreading like wildfire with up to 50 000 new daily cases reported,
hospitalisations have more than halved with hospitalization rates more than
twice as high in unvaccinated people compared to those who have received two
doses of a vaccine.

Referring to South Africa’s expected 4th
wave, he reiterated that its severity would depend on the potential circulation
of a new variant and the effectiveness of the current vaccines to protect
against it.

“If Delta is all that we have to deal with
in future, we can go back to normal quite quickly. There will be endemic
transmissions and we will see small outbreaks, but they will be containable
with boosters to protect against waning immunity. That is the best-case
scenario. The worst-case scenario is that variants continue to create new
variants which could be driven by patchy vaccine coverage, countries with low
vaccine coverage and waning vaccine immunity,” Prof Karim noted.

However, the most likely scenario, he
suggested, is that the virus will be with us for many years to come with a few
new variants emerging. This could include vaccine escape mutants but with
decreased transmissibility as new vaccines and boosters become available with
the virus eventually getting to a point where it will stop mutating and fades
away.