“Vaccines remain the most clinically effective and cost-effective biomedical intervention to mitigate the impact of the epidemic”

Dr Shameem Z. Jaumdally – Senior Research Scientist
Centre for Lung Infection and Immunity, Department of Medicine & UCT Lung Institute, University of Cape Town

* ‘The C.1.2 variant is almost undetectable in South Africa…
it has very quickly been swept aside in by his Delta ‘cousin’ which proved to be much fitter to take hold in community spread

 * ‘I highly recommend that all people who are at greater risk of developing severe disease get their booster shot

Senior Research Scientist Dr Shameem Jaumdally, based in South Africa, makes a detailed overview of the current Covid-19 situation, covering all aspects from prevention to treatment. Importantly, echoing other voices too he makes a plea for preparedness in view of further waves that are expected, and lays stress on the need for cross-cutting institutional collaboration and for basing policy decisions on scientific evidence. Read on…

* The local Covid situation appears to be extremely serious, as evidenced by the current wave with increasing numbers of people becoming infected and the number of deaths, among both young and old alike, on the rise. What’s your assessment of the situation as a virologist?

In the absence of a reliable report on the number of daily new cases, the next best indicators we are left with to get an understanding of where we are in the current wave remain our hospital admission and death rates. The trends show that we have now reached our peak in the number of daily cases. However, a lag of 7-10 days from infection to hospitalisation, and a further 4-7 days until demise, are indicative that both these statistics will increase in the coming days. A decline in both is expected in early December. The heterogeneity in the profile of casualties (young and old, urban and rural residents) points to a widespread distribution of cases across the island.

 * When the first wave hit last year, it was known who was “patient zero”. This time round, it would seem the authorities may be at odds about what led to the resurgence of the disease, and more specifically, who is “patient zero”. What are your views thereon?

Past a successful dissemination of the virus across the island and the establishment of regional clusters, it matters little who was patient zero. The most likely scenario for the introduction of the Delta variant in the community would have involved hotel staff who had interactions with infected tourists/returning citizens coming to our shores during the resort quarantine period.

It is also important to highlight that tourists and returning residents are actually the least risky group, given that they are tested prior to travel, at arrival and a further few days into their stay in the country. We should not fall into the trap of believing that tourists are the reason of what we are experiencing now. The likelihood of a community transfer was always higher from a returning citizen who interfaces with the community at a higher frequency.

* Is this wave due only to the rapid spread of the Delta variant or are there other factors involved?

A combination of Delta’s increased transmissibility (on account of an up to 100-fold higher viral load) and a lack of effective restrictive measures have, in my view, led to an exponential rise in community transmission. This translated in the expected steep rise in hospitalisation and death due to Covid-19 that we are experiencing now.

* How does the Delta variant compare with the first Covid-19, and are there likely to be other more deadly variants?

The Delta variant has not been found to cause more severe disease in people it infects. The higher casualty rate is merely linked to the greater number of cases. Mutations in the genome of the Delta variant do however confer a better resistance to vaccines, where vaccine efficacy against both infection and the progression to severe disease is rendered lower.

* A threshold of 700,000 persons vaccinated had been set for the country to achieve herd immunity. Almost 70% of the population have been fully vaccinated, and about 42,000 have received the booster shot. But now we are told that vaccines, though vital, are not a “perfect panacea”. How do you react to that?

Because we are dealing with an epidemic caused by a novel virus, the targets have always remained moving ones. The sheer spread of the virus around the globe has led to the emergence of several mutants.

At the initial stage of vaccines roll out, the hope was that we would have vaccines that provide sterilising immunity, which is protection against infection. Waning vaccine immunity over time, especially in a more at-risk population (older age and comorbidities) also complicated the attainment of this now elusive herd immunity. Global vaccine efficacy has however remained very high, well in excess of 90% against death due to Covid-19.

At the moment, vaccines remain the most clinically effective and cost-effective biomedical intervention to mitigate the impact of the epidemic.

* But if vaccines remain vital for self and community protection, what do we know about the efficacy of the vaccines available in Mauritius against the Delta variant, and what would you recommend for the booster shot?

The vaccination program in Mauritius is unique in the sense that we have made use of a variety of vaccines. As known from the get-go, inactivated vaccines (Sinopharm and Covaxin) have a lower efficacy than the viral vector-based systems (AstraZeneca/Covishield, J&J, Sputnik). mRNA jabs with the highest efficacy, in this case Pfizer, have been rolled out for teenagers and will now be made available as a booster for more vulnerable population and highly exposed healthcare workers, and also for pregnant women.

Vaccines modulate the immune system in different ways. One component of this, the level of neutralizing antibodies in the systemic circulation, is thought to be central to protection against both infection and severe disease. This level goes down over a period of 6-8 months and that is why a booster shot is recommended for the more at-risk individuals to guarantee optimal protection on exposure.

Real life efficacy measured through epidemiological outcomes and laboratory assessment have confirmed that efficacy against Delta has only marginally decreased compared to the wild type strain (original Wuhan virus against which vaccines were developed), but efficacy against transmission has gone down significantly on account of the changes mutations have conferred to the different variants.

From my experience, I highly recommend that all people who are at greater risk of developing severe disease get their booster shot.

* Government has come forward two weeks back with some measures to stop the spread of the virus in the country. Do you think these are sufficient given that the Delta variant could be more aggressive and much more transmissible than previously circulating strains?

The pace of transmission and its widespread nature over the last weeks have demonstrated that these measures were clearly not sufficient. I feel that the Mauritian population at large still struggles to grasp the basic concept of what leads to increased transmission potential. Citizens were told that outdoor events were safer, and soon after we saw them camping on the beach in large groups, dropping mask wearing, devoid of a proper access to water or sanitizer, and crowding in tents at night time. This was one of the many examples that provided the perfect breeding ground for the superspreading of Delta. Gatherings of up to 50 people, while permissible, also contributed to an unchecked spread of the virus.

The population needs to understand that in a time when the positivity rate is so high (20%+ if you consider rapid testing alone) the risk is more than real! Any event that involves the sharing of a meal is one that is at heightened risk of transforming into a superspreading meeting. Gathering of over 50 means that people from different households will meet. Nobody will convince me that all of these indoor events (de facto behind closed doors and away from public scrutiny/legal enforcement) will have all the proper sanitary measures to guarantee a safe environment.

The biggest fallacy of this new set of measures was the size of gatherings. Every measure we put in place to curb spread should have this target as a premise. And these should be applied consistently across the new protocol. It confused people and sent the wrong signal when only 10 congregants were permitted at places of worship and yet grouping of up to 50 were permissible for social reasons. The temporary closure of schools was a good measure. It upsets me to hear people use the rhetoric of allowing full capacity in public transport as an excuse to meet up in smaller groups for social reasons, claiming they are at lower risk of exposure. It highlights the fact that they do not understand much about the transmission of this virus!

Don’t get me wrong, I am not saying that having packed buses is ok at the peak of a wave with a respiratory virus, but in a reduced capacity, with proper aeration, a non-negotiable wearing of mask and effective sanitization, we can safely allow for the provision of this essential part of around half a million people’s life, daily users commuting for work mostly. This counts as an essential part of our economic continuity and survival.

* What else do you think should be done in order to bring the current situation under control as rapidly as possible?

In South Africa, where I am based, our restrictions are tailored to fit what research has taught us regarding transmission. For instance, epidemiological research has highlighted that settings involving the consumption of liquor are at greater risk of being superspreading sources for Covid-19. Based on this knowledge, it was decreed that the sale of liquor from Friday to Sunday would be banned across the country. This measure was also in line with freeing up more beds in ICUs to deal with an increasing Covid-19 hospital burden instead of being used by a victim of alcohol related trauma such as drunk driving, homicide, or gender-based violence, all societal issues rampant across the rainbow nation.

What I am saying is that measures need to fit the desired change in behaviours that we expect, because lest we forget, Covid-19 is very much a behaviour dependent epidemic. My first suggestion is the instauration of a curfew from sunset to the early hours of the morning for the right period, started at the right time. This will allow essential movement for economic activities to continue while keeping in check the unnecessary gathering of people during the different waves we will experience.

Work from home should be prioritized for people at risk. A durable strategy for work/study from home should be established and I emphasize the ‘durable’ aspect because we will need to switch to this mode every time we go through a resurgence in cases. Businesses like food outlets and bars/pubs should operate with a limited seating capacity. Very strict sanitary protocols should at all times be enforced in these spaces to allow for a tangible operational framework, and one that can work!

I appeal to people to adopt a pray-at-home option when necessary and I remind them that our different faiths have made provision for this. It is holy to protect oneself and those around us. Every effort matters, big or small. Finally sports and leisure group activities, even when practised in outdoor settings should be avoided.

* In view of the evolving characteristic of the coronavirus, what do you think should be undertaken to equip the country and its health authorities face any future strains of the virus?

We are at war against an enemy that we do not understand fully. It displays characteristics that makes it fitter as it evolves. It is invisible, it can infect incognito and further remain incognito (asymptomatic status) while being transported around for its next strike. But concerted efforts from the research community across the world, a focused effort on deciphering the characteristics of this novel virus and large scale sharing of data and experience in the fight against this microbe have contributed to providing more effective strategies, biological or otherwise.

Most countries that have navigated through this Covid-19 storm have chosen right from the beginning that their reaction to the epidemic will be guided by science and research. Without a proper understanding of what the situation is on the ground, no effective war plan can be devised. This intel can only be garnered through the mass collection of data and rigorous analysis and data mining. Professionals with the right training and experience should be invited to come on board for this. The biggest stakeholder that comes to mind in this case is our research community across the multiple universities and comparable institutions on the island. Insurance companies have access to big data for their medical aid holders and a team of highly trained actuaries. Let’s use all these resources!

I have no doubt that, if called upon, all these people will not think twice to take their spear and head to war. The best way to mitigate the impact of this epidemic is developing a capacity to predict and plan. Forecasts are reliant on the generation of high-quality data and its rigorous analysis. The independence of this process is key to establishing a solid ‘rapport de confiance’ with the population.

* If we are going to learn to live with the coronavirus as well as keep updated with its variants circulating in different countries, does it also mean that we would likely have to get a booster vaccine at regular intervals in the future?

It is known from the Israel experience, four months ago, that the holy grail of herd immunity is unachievable. Vaccines have their limits while still providing a high level of protection against severe disease and death. Covid-19 is here to stay. It will become endemic in the next two years. This means it will be like the seasonal flu and possibly come with similar challenges, such as constant mutations in its genome.

On the vaccine front, the most likely scenario right now is the design and regular (yearly) update of a polyvalent vaccine generated against a cocktail of the most prevalent strains at the time, as we have for seasonal flu. Vaccine designs are being improved to minimize the occurrence and severity of side effects and increase vaccine efficacy.

A recent breakthrough in treatment in the form of the drugs Molnupiravir and Paxlovid is welcome news to palliate for vaccine failures in the most vulnerable group. The administration of a therapy is far less challenging than a vaccine program. But we should remind ourselves that Covid-19 leaves behind long term sequelae even in young otherwise healthy individuals and a vaccine works best with its avant-garde mechanism of action.

* It’s unlikely that a silver bullet may be in the pipeline any time soon, right?

As a trained virologist I will state that the only weapon that will fulfil the potential of a silver bullet will be an effective antiviral. We are seeing rapid progress in that endeavour. Until these medicines are accessible, we need to stick to what is known to work. Preventive measures, mostly self-imposed, are the best strategies right now.

We talk about the new normal, but it is evident that the population is not going about it academically and pragmatically. Academically: are we changing our behaviours effectively, pragmatically in the sense of practicality and durability? A new normal means learning to live when case counts are low and likewise when they go up. The implementation of a graded warning system, driven by evidence and attached to grade-dependent set of restrictive measures would go a long way in helping the population transition into this new normal. They need to be educated, provided with a clear rationale of why restrictions are being implemented. Practical choices, such as having a wedding when one wishes to, should rather be dictated by when it is safest to have them.

We will need to learn to make use of the reprieve we get between waves of Covid that will hit us. Global experience is warning us that we will experience at least two of these every year for at least two more years. We have been warned. It is time to act accordingly.

* In the meantime, there’s another challenge that will have to be overcome in the fight against the pandemic: inaccurate, or misleading information, false rumours, and gossip, like the one presently circulating on social media presently in Mauritius about “a new highly mutated variant” of the Covid-19 virus having been identified in South Africa — the C.1.2 variant, which would be already active in seven other countries across Africa, Asia and the Pacific regions. Is that indeed the case, and would it be more severe than the Delta variant?

Along with the viral epidemic that we are experiencing, a parallel epidemic of fake news and disinformation has slowly but surely garnered support, and the wave has been unabating for this mostly epistemological problem. A lot of this emanates from antivaxxers or anti-lockdown anarchists who have a sinister agenda to push forward.

In the case of the C.1.2 variant, while it was in the news around three months ago for being the most mutated variant of the virus, it has very quickly been swept aside in South Africa by his Delta ‘cousin’ which proved to be much fitter to take hold in community spread on account of its higher transmissibility. Now, this variant is almost undetectable in South Africa. This shows how quickly things evolve during an epidemic of this nature and why it is important to constantly update ourselves with the most recent findings.

* Published in print edition on 23 November 2021

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