Experts say the older a person is, the more likely a vaccine will not be effective when administered on them.
This is contained in a study published in peer-reviewed online journal BMJ.
The United States Centres for Disease Control and Prevention had said that eight in 10 COVID-19-related deaths reported in the country had been among people aged 65 years or over.
In the United Kingdom, study says, just being 70 years old or over puts someone in the medium risk COVID-19 group.
Speaking on the issue, Director of the Lydia Becker Institute of Immunology and Inflammation at the University of Manchester, Tracy Hussell, says, “Studies have shown that age alone is the most significant risk factor for severe disease, and generally, this is the same with other coronaviruses and influenza viruses that affect the elderly.”
She says this could be because of the increased likelihood that a person will have comorbidities in older age, many of which are linked to poorer COVID-19 outcomes.
It may also be due to the medications that some of these patients take for their comorbidities, an area where Hussell thinks there is a lot more to learn.
However, it may also be due to the ageing immune system.
“In older age, the viral alert signals aThe World Health Organisation Regional Director for Europe, Dr. Hans Henri P. Kluge, said though the majority of those who are infected with COVID-19 have “a self-limiting infection and do recover,” a minority go on to suffer more severe diseases, with 10 per cent of cases requiring intensive care unit admission, noting, “sadly, some patients will pass away.”
Continuing, Kluge warned, “Older adults are at a significantly increased risk of severe disease following infection from COVID-19.”re much slower. And if you mount a very slow immune response, then you end up with greater viral replication,” researchers say.
The immune cells that also take up the virus, the macrophages, are known to be slower in age.
“And this decline in the immune function is quite well known; it’s called immune senescence,” Hussell explains; adding, “As we age, the thymus, which sits just above the heart and pumps out T cells, shrinks in size, decreasing the number of T cells it releases.
“This in turn affects many other aspects of the immune system.”
Asked if old age could reduce the effectiveness of a vaccine, Hussell responds in the affirmative.
“Yes. Age will certainly affect a response to a vaccine, because a vaccine is trying to induce protective immunity.
“The immune system decreases with age, and so recognition and response to a vaccine are also reduced.
“The other thing is that a lot of old people are taking anti-inflammatory medications, and these may reduce anti-vaccine immunity as well.”
“We also know from reports that eight out of 10 deaths are occurring in individuals with at least one underlying comorbidity, in particular those with cardiovascular diseases/hypertension and diabetes, but also with a range of other chronic underlying conditions,” Kluge added.
According to Kluge, a family physician and infectious disease expert before his WHO appointment, some of the reasons older people are greatly impacted by COVID-19 include the physiological changes associated with ageing, decreased immune function and multi-morbidity which make older adults to be more susceptible to the infection itself and make them more likely to suffer severely from COVID-19 disease and more serious complications.
Experts, however, note that age is not the only risk for severe disease.
“The very notion that COVID-19 only affects older people is factually wrong, as young people are not invincible.
“Ten to 15 percent of people under 50 have moderate to severe infection.
“Severe cases of the disease have been seen in people in their teens or 20s, with many requiring intensive care and some, unfortunately, passing away,” Kluge said.
On a positive note, there are reports of people over the age of 100 who were admitted to hospital for COVID-19 and have now made complete recovery.
Physicians say it is becoming clearer that the healthier an individual was before the pandemic plays a crucial role.
“People who age healthily are less at risk,” they said.
Indeed, last December, the Nigeria Centre for Disease Control said the agency had started seeing increasing transmission among younger people, warning, “this is not considered good and safe.”
Earlier in January, NCDC Director-General, Dr. Chikwe Ihekweazu, said the agency had noticed a surge in COVID-19 cases in settings such as schools and offices.
He had said, “In the last two months, there has been a spike in the number of COVID-19 cases across the country.
“This has affected nearly every state in the country. We also detected an increase in the number of cases in closed settings such as schools and offices.
“The decision to keep schools closed was to, among other things, enable us to control this rapid spike in cases while reducing the risk to children and school staff.”
Nigerian authorities had said frontline health workers would be among the 40 percent of persons scheduled for the first batch of the COVID-19 vaccine.
Meanwhile, the date of arrival of the first batch of vaccines remains uncertain as the World Health Organisation had removed Nigeria from the list of African countries to receive the Pfizer-BioNTech vaccine.
The WHO cited lack of proper storage for the Pfizer brand vaccine, saying it could not afford to have it wasted.
The Pfizer-BioNTech vaccine is to be stored at -70 Celcius.
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