Unvaccinated South Africans have a five times higher risk of COVID-19 infection and 20 times higher risk of dying from COVID complications than people who are fully vaccinated with the Pfizer/BioNTech vaccination. And, according to the real-world study by the medical scheme, the Pfizer/BioNTech vaccine reduced the risk hospitalisation or death from COVID-19 by more than 90%.
People who had received both shots of the two-dose jab had a 92% lower risk of hospitalisation and 94% lower risk of death from COVID than those who had not been vaccinated, up to three months after immunisation. Even a single shot offered significant protection, reducing the risk of hospitalisation by 73% and that of death by 79% after 14 days, found the study.
Business Day reports that these findings are consistent with a US study published in The Lancet in October, which found the effectiveness of two doses of the Pfizer vaccine against hospitalisation remained high even at six months, at 93%. The findings emphasise the importance for SA of rapidly scaling up coverage.
By November 3, SA had administered 22.8m vaccine doses and fully immunised 31.7% of the adult population with either the two-dose Pfizer vaccine or the single-shot Johnson & Johnson jab.
The government had hoped to vaccinate 70% of adults by the end of the year, but Discovery Healthʼs projections estimate it will reach only 52%, said CEO Ryan Noach. “That is a concern for lives and livelihoods, because vaccination is the most important tool we have to return to normal life,” he said.
The SA study included more than 1,2m adults who had received the Pfizer vaccine, from the start of the governmentʼs vaccine rollout on 17 May to 23 September, coinciding with the country’s third surge in infections, dominated by the Delta variant.
The study found no waning in vaccine effectiveness at protecting recipients against COVID-19 hospital admission and death in the three months after the second dose. University of Cape Town head of infectious diseases Marc Mendelson said Discoveryʼs findings are in line with global evidence.
“It is highly encouraging in terms of hospitalisation reduction and death, but it is a short follow-up period. The key issue now is how protection wanes, and we expect it will do the same [in SA] as it has done elsewhere,” he said.
Discovery Healthʼs analysis included 526,516 COVID-19 tests, 14,673 COVID-19 hospital admissions and 3,441 COVID-19 deaths. It found vaccinated men and women were at equal risk of hospital admission and death from COVID-19 and that vaccinated people with chronic conditions were no less protected than people without these underlying illnesses.
However, vaccinated people with three or more underlying conditions had more risk of hospitalisation and death from COVID, as did vaccinated people over 80. Vaccinated people who had recovered from COVID before getting their shots had a far stronger immune response than those who had never been infected: their relative risk reduction in hospital admission for COVID-19 was 98%.
Prior infection does not guarantee immunity, added Discovery Health chief health analytics actuary Shirley Collie, as 11,500 Discovery Health members had tested positive for COVID-19 a second time and 37 had tested positive three times.
Collie, said they found the Pfizer vaccine is 73% effective in protecting against the risk of admission to hospital from Covid-19 from 14 days after the first dose and 92% effective from 14 days after the second dose. The vaccine is 79% effective in protecting against Covid-19 mortality from 14 days after the first dose and 94% effective from 14 days after the second dose.
“There is a stabilisation in vaccine effectiveness protecting against Covid-19 admissions and mortality at 28 days after Dose One and at 14 days after Dose Two,” she said. There was a 5% to 7% decline in vaccine effectiveness in protecting against admission to hospital in people over the age of 80, and in individuals with three or more chronic conditions.
Collie said unvaccinated people who had a prior Covid-19 infection had a lower relative risk of hospital admission. People who had had Covid-19 and got vaccinated, she said, developed a 98% protection against the virus.
Collie said 11,500 members of their medical schemes had tested positive for Covid-19 twice more than 90 days apart and 37 members had tested positive for Covid-19 three times.
Dr Ronald Whelan, the head of Discovery’s Covid-19 task team, said of the three statistically significant side effects reported to them, swelling of the lymph nodes was the most prevalent, followed by inflammation of arm muscles and tingling in hands and feet. People who contracted Covid-19 were more likely to experience these symptoms than those who had the vaccine.
Potentially fatal Covid-19 complications like pulmonary embolism (blood clot in the lungs), acute kidney injury, anaemia, heart rhythm disturbances and myocarditis (inflammation of the heart muscle) were also more prevalent in people with Covid-19 than as a side effect of the vaccine.
Whelan said there were very few adverse vaccine-related events reported at the Discovery sites and no vaccine-related deaths.
See more from MedicalBrief archives:
Vaccination 5x more effective against hospitalisation than prior COVID infection — CDC analysis
99% strong immune response after Pfizer vaccination — UK's PITCH study
Single shot of AstraZeneca or Pfizer-BioNTech vaccines reduce hospital treatment for elderly
‘Not a single vaccinated person in COVID-19 high care ward’ — Groote Schuur doctor