Long way to go: A Johannesburg resident is tested for Covid-19. About three million people (4.4% of the population) are fully vaccinated and herd immunity is achieved at 67%. Photo: Marco Longari/AFP/Getty Images
At current rates South Africa might only vaccinate 67% of its population to reach herd immunity by March next year. But even when that goal is reached, a return to normality cannot be guaranteed.
Experts are advocating that people continue to wear masks, wash or sanitise their hands, maintain social distancing and avoid crowded and poorly ventilated areas. Global data shows that countries far ahead of South Africa in vaccinating their populations are still experiencing resurgences of Covid-19, though at reduced levels.
With more than eight million people in South Africa already vaccinated, 2.8-million Pfizer doses of the 5.6-million donated by the United States government have been used.
About 1.5-million doses bought from Pfizer are expected to be distributed next week, while more than 1.4-million Johnson & Johnson doses were distributed this week.
The South African vaccine roll-out has recovered from a disappointing start to reach an almost smooth trajectory.
As more cohorts become eligible for vaccination — with the 18 to 34-year-old group joining the queue from 1 September — the Mail & Guardian spoke to experts about what can be expected with the revised target of 67% of the population vaccinated to reach herd immunity.
Herd immunity explained
Dr Andrew Musyoki, the deputy head at the South African Vaccination and Immunisation Centre, said herd immunity was reached when a population gained immunity status against an infection. When this happens, the people who are immune form a barrier around those who are not immune to the infection.
“With the current vaccination status at over seven million administered doses, barely three million of these are fully vaccinated. The current national vaccination coverage is just over 4.4%. So, we still have a lot to do to achieve herd immunity,” Musyoki said.
Is it too early to talk about herd immunity?
South Africa’s roll-out campaign is currently reliant on two vaccines: Johnson & Johnson, which is a single dose, and Pfizer, a two-dose vaccine. This current strategy, according to experts, means that even if the projected 40-million people were vaccinated by December, this would not mean the entire population would be fully vaccinated.
And even with more than seven million people vaccinated, not all have had the full dose.
Based on calculations by Dr Ernest Darkoh, the founder of the BroadReach Group and a public health expert, if the Pfizer vaccine was the only one being used in the strategy, roughly 248 000 doses would need to be administered daily to vaccinate the remaining 32.7-million with one dose by the end of December.
“Given that the private sector is just beginning to ramp up, it looks like the country will be able to administer at least one dose to 40-million people by 31 December. This [is] assuming no major supply interruptions and all the people actually show up and are ready to be vaccinated.
“However, South Africa will not be at herd immunity because this number will include a mixture of fully vaccinated people and partially vaccinated people — those who still need a second dose,” said Darkoh.
The 31st of March next year is now the latest target date according to data provided at the end of July by the Council for Scientific and Industrial Research on vaccinations trends and projections.
But, according to Musyoki, in the instance of Covid-19, a projection of over 80% vaccination coverage would be needed to achieve herd immunity in South Africa.
Will herd immunity allow us to go back to normality?
No. Although some restrictions might be eased in the event where herd immunity is reached, and the threat of a resurgence minimised, public health measures are more likely to remain beyond Covid-19.
According to Musyoki, the emphasis on the factors to achieve a herd immunity threshold, such as the contagiousness (transmissibility) of the virus against vaccination coverage and population immunity, could result in the easing of most of the restrictions.
“If we so badly long for the days without restrictions, we need to take a collective stance to demand that all eligible persons take the vaccine. This is a moral stance to protect our vulnerable elderly and those who cannot be vaccinated.”
Darkoh suggested that some measures be kept in place because of the possibility of the virus becoming a part of our lives in the future in the way the seasonal flu virus is.
“I strongly suggest that certain key recommended public health measures [wearing masks, washing and sanitising hands, physical distancing and staying in well ventilated spaces] are maintained for a long time after herd immunity is achieved.
“Given what we have learned about how quickly new aggressive strains can emerge, we will only be truly safe if the very last virus particle is eliminated globally. This will require us to strictly adhere to many of the current recommended practices for a very long time to come,” he added.
Darkoh emphasised that vaccines would not prevent the spread of the virus, including in the vaccinated groups.
“It is important to note that being fully vaccinated does not prevent someone from getting infected with the virus or from being able to transmit it to others. It [being vaccinated] means that once infected they are likely to have a mild case or [an] asymptomatic case and not die or require hospitalisation.”
The department of health’s spokesperson, Popo Maja, also cautioned that having unvaccinated people meant the risk remained of a resurgence and breakthrough of infections in vaccinated populations.
“Depending on the rate of infections and mortality, certain aspects of the lockdown may be reconsidered.”
Are there lessons to learn from nations that vaccinated earlier than us?
The United States’ vaccination rollout started in December last year when the death toll stood at more than 300 000 people. The current death toll is about 613 000. Preliminary data released by the US Centers for Disease Control (CDC) showed that 99.5% of Covid-19 deaths between January to June this year occurred in unvaccinated people and 4 427 people were hospitalised as of 28 June.
The CDC further reported that Covid-19 cases were being seen in fully vaccinated people, and other analysis found that fewer than 1.1% (1 200) people were admitted to hospital and only 0.8% (150) of deaths were of vaccinated people.
Similar findings were made in countries such as the United Kingdom where a preliminary study found that fully vaccinated essential workers were protected by up to 90% against infection.
Partially vaccinated people were less likely to be infected by at least 78% than unvaccinated people.
Israel started its vaccination programme before any other country and has been closely watched. It has now become the first country to administer booster shots to previously vaccinated individuals who are 60 and older.
Speaking on current affairs programme Face the Nation on CBS News, Israel’s director of public health services, Dr Sharon Alroy-Preis, said that observations over the past couple of weeks showed that there was waning immunity, especially among the older members of the population.
“It’s not just the fact that we’re seeing more disease, but they’re getting to severe and critical conditions,” said Alroy-Preis.
She said the infection rate among those who were fully vaccinated by the end of January, was at 90 per 100 000, double that of those who were fully vaccinated in March. Another factor to consider was the fact that the Delta variant had been found to be 50% more infectious than the Alpha variant, which was also 50% more infectious than the original virus.
Israel is learning as data comes through that fully vaccinated individuals were not as well protected as previously thought.
“We are seeing about 50% of the people who are infected right now are fully vaccinated individuals. Previously, we thought that fully vaccinated individuals are protected. We’re now seeing that the vaccine effectiveness against disease is roughly 40%. It still remains high for severe disease,” Alroy-Preis said.
Globally more than four billion people have been vaccinated with at least one dose.
Darkoh said: “The data is stunning. Almost all the deaths are occurring in unvaccinated people. This tells us that if we mount an effective vaccination programme and get South Africans vaccinated as quickly as possible, we can stop Covid-19 deaths just as quickly.
“We should use this data as part of our public education campaign to encourage anyone who is on the fence to come forward to get vaccinated.”
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