The benefits of vaccines still far outweigh the risks, experts say following the recently reported death linked to a COVID-19 vaccine.
The South African Health Products Regulatory Authority (SAHPRA) announced two weeks ago that the individual developed Guillain-Barré syndrome (GBS) after receiving the Johnson & Johnson (J&J) vaccine. It is the first death in the country that has been causally linked to a COVID-19 vaccine.
Since the announcement, some groups opposing vaccines have taken to Twitter and other social media platforms using this very, very rare adverse event following immunisation as confirmation of their stance that vaccines are not safe. Local health experts have raised concerns that these groups may negatively affect vaccine uptake.
Over 38 million doses of COVID-19 vaccines have been administered in South Africa, of which more than nine million were the J&J vaccine.
According to SAHPRA, GBS is a rare condition affecting the body's immune system. Symptoms of GBS can vary from mild to severe, and include muscle weakness, muscle pain, numbness, and tingling. In many cases, GBS gets better with no serious after-effects but in some cases, GBS can become serious and cause paralysis and other serious or life-threatening problems. In the case of GBS-associated paralysis, an extended hospital stay and intensive care with ventilatory support might be necessary, which can subsequently be complicated by infection, which can be life-threatening.
A known risk
Last year, the United States Food and Drug Administration (FDA) revised its fact sheets for the J&J vaccine. In a press statement dated 31 July 2021, the FDA said it had included information pertaining to an observed increased risk of GBS following vaccination.
The 2021 statement said there were about 100 preliminary reports of GBS in the US related to 12.5 million doses of the J&J vaccine. Of these, 95 were serious and required hospital admission. There was one reported death. The Australian government in a vaccine safety report said two deaths were linked to GBS following administration of the AstraZeneca COVID-19 vaccine, which is not used in South Africa.
One fatal case of GuillainBarré syndrome recorded following J&J #COVID #vaccine. Important to stress this is one case of over 9mil doses administered in SA where causality was established. @SAHPRA1's CEO Boitumelo Semete:"The benefit of the vaccine still far outweighs the risk." https://t.co/ZVzmKCsDaK
-- Spotlight (@SpotlightNSP) August 4, 2022
'Very, very rare'
Professor Charles Wiysonge, senior director at the South African Medical Research Council (SAMRC), says, "The one death in the 9 135 189 doses of J+J vaccine delivered in South Africa has to be seen in context. The risk of fatality from a J+J vaccine is 1 in over 9 million - which is very, very rare, and while any death is unfortunate, the rare risk of fatality talks to the success of vaccines."
He says the adverse event also needs to be seen in the context of the number of people who have died from COVID-19. "At the SAMRC we estimate that there have been more than 300 000 excess deaths which are attributable either directly or indirectly to COVID-19."
Findings from the Sisonke J&J study published in the Lancet in March show the benefit of the vaccine with 83% protection against death, 75% protection against critical intensive care admissions, and 67% against hospitalisation. The study was conducted at the time when the Beta variant was circulating, the variant having had an effect on the efficacy of the vaccine.
"The rigorous monitoring and safety of all health products is one of SAHPRA's priorities and checks and balances are in place," says Wiysonge.
How the process works
In a process called causality assessment, the National Immunisation Safety Expert Committee (NISEC) specifically reviews and assesses severe adverse events reported after immunisation and establishes whether or not they are associated with the use of a vaccine.
SAHPRA works closely with both the National Department of Health and NISEC to ensure that all reported severe adverse events are firstly investigated by the provinces and thereafter assessed for causality by NISEC. Causality assessment of the reported case was conducted by the NISEC using the World Health Organization (WHO) methodology, which is a systematic step-wise process.
NISEC committee member Professor Hannelie Meyer explained the process as follows: The first step is to confirm the diagnosis of the reported event, which in this case was GBS.
Next is to determine if the event occurred within a plausible time risk window after vaccination, which is based on reported literature. Thereafter, evidence against a causal association is considered, which means that there must be strong evidence to rule out any other causes for GBS such as a bacterial or viral infection.
"In this case, no other cause of the GBS could be identified at the time of the illness. Following this, the vaccine administration process and storage conditions are considered to rule out any programmatic errors that could have caused a particular event," she says.
Thereafter, the published literature and the product information are reviewed to determine whether the event is a known adverse event linked to the particular vaccine. "In this case, GBS is listed as a very rare adverse effect of the J&J vaccine," she says.
The person's medical history, based on medical records, is then reviewed to determine whether there are any other qualifying factors such as underlying chronic conditions or medication that could also have caused the particular event.
The final step is to consider all evidence available and classify the case as either causally linked to the vaccine, coincidental to vaccination, indeterminate when there is some evidence but not sufficient definite evidence to confirm causality, or unclassifiable if the information available about the case is insufficient.
Hesitancy
Vaccine hesitancy has been attributed to concerns about vaccine safety, perceptions of high vaccine risks, and low disease risk and consequences. Even when the public believes vaccines are important for protection many still have concerns about vaccine safety.
The chances of dying in a motor vehicle accident are far greater than the risk associated with a vaccine, and yet people are more willing to accept the risks of motor vehicle accidents
Wiysonge says decision-making about vaccines is influenced by heuristics or cognitive biases, which are mental shortcuts that allow people to solve problems and make judgments quickly and efficiently when faced with uncertainties and risk.
He says, for example, "risks that are common or familiar are more acceptable to people than risks that are uncommon or unknown".
"The chances of dying in a motor vehicle accident are far greater than the risk associated with a vaccine, and yet people are more willing to accept the risks of motor vehicle accidents," he says.
According to a study published in the Lancet, GBS has a worldwide annual incidence of 1.2-2.3 cases per 100 000, which increases to 3.3 per 100 000 in adults over 50 years. We could not find reliable GBS estimates for South Africa.
The disease is relatively rare (In the United States 3 000-6 000 people develop the condition every year) but it can be severe, according to a paper published in the journal Brain.
Professor Rose Burnett at the Virology Department at Sefako Makgatho Health Sciences University says that over 60% of cases of GBS, an auto-immune disease, are triggered by respiratory or gastrointestinal infections, including those caused by viruses such as SARS-CoV-2, cytomegalovirus, Epstein Barr, Zika and influenza viruses.
She says, while a small minority of cases have been associated with therapeutic agents (for example, 1 in 1 000 patients receiving immune checkpoint inhibitor therapy for cancer) and vaccines (1 in 100 000 of those receiving the 1976 H1N1 influenza vaccine, and fewer than 1 in 1 million of those receiving other influenza vaccines), "we don't know what triggered the remaining cases".
"It is possible that GBS may be triggered by as-yet-unidentified viral infections. It's one of those horrible diseases where we don't fully understand the underlying causal mechanisms, but we know there are viral infections that are associated with it.
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"So, when the vaccine precedes a case of GBS and none of the associated triggers are present, we can say GBS is probably related to the vaccine," Burnett says.
A study based on Vaccine Safety Datalink surveillance data on 15.1 million doses of COVID-19 vaccines, shows there were more cases of GBS after the J&J vaccine than the background of naturally occurring GBS - in other words, what we would expect to see if there were no vaccines - whereas after the Pfizer vaccine there was no increase from what occurs in the general population, says Burnett.
"So, it's highly likely that there is an increased risk for GBS when using the J&J vaccine. However, this very small risk must be balanced against the much larger risks of severe disease and death from COVID-19," she says. "If the J&J was the only COVID-19 vaccine available to me, I would definitely take it."
Burnett says death after vaccination is almost unheard of but can be caused by untreated anaphylaxis, a severe allergic reaction to one or more constituents of the vaccine.
"Anaphylaxis is not something that will go untreated in most of the world. I think there's no vaccination clinic in the world that would be operating without an emergency kit. It is very seldom that it will ever result in death. It would be rare as most health facilities are equipped with adrenaline to treat anaphylaxis and there are no long-term effects.
"It is like having a peanut allergy or shellfish allergy. It's something that you get treated for and immediately you are better. So death after vaccination is just so rare and only likely to occur in exceptional circumstances," she says.
Meyer says many people are often worried about the risk of experiencing a very rare adverse event following immunisation and want to know what their individual 'chance' of developing such an event like GBS is following immunisation. "This is something that is not known, because these events are so rare. The same applies to other life-threatening allergies such as bee stings, nuts, and seafood. One will not know if you have such an allergy unless you are exposed to the allergen," says Meyer.
