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16 September 2021 | Story Nonsindiso Qwabe | Photo Supplied
Dr Samantha Potgieter.

As COVID-19 vaccines continue to be a topical issue in South Africa and indeed in the world itself, the Department of Human Resources held a webinar for the UFS community on 10 September that delved deeper into the questions surrounding the vaccine. 

Dr Samantha Potgieter, infectious disease expert at the Universitas Academic Hospital and affiliated Lecturer in the Department of Internal Medicine at the University of the Free State, addressed some commonly raised concerns about the COVID-19 vaccine and how it affects us.

Dr Potgieter started off by saying that coronaviruses have been causing outbreaks among humans for millennia. While COVID-19 is relatively mild and self-limiting in 80% of patients, 20% of patients are at risk of developing severe disease.
She said before a vaccine could be introduced to a population, it had to go through rigorous testing and clinical trials. Only once safety has been confirmed, it can be released and distributed. 

“This process usually takes about ten years; this is what we are used to. But it has happened much quicker for the COVID-19 vaccine, and I think this is a fact that many people misinterpret – that the evidence might not be that robust, which is certainly not the case. COVID-19 vaccines have gone through all this rigorous testing, thousands of patients had volunteered for trial testing studies. The point is that we already had the technology, vaccination is not something new to humans. So, these preclinical trials were able to happen very quickly, and because of the large number of infections and because the focus of the entire world was on finding a cure, it was a very set process to get these trials through the adequate phases.” 

She said the COVID-19 vaccine was approved by national regulators, manufactured to exacting standards, and only thereafter distributed – as is the case for all drugs released into the market.

How does the vaccine work?

Dr Potgieter said the vaccine works by producing antibodies against the COVID-19 virus. If you are infected with the COVID-19 virus after getting vaccinated, these antibodies bind to the virus and stop it from replicating.

“When you get infected with a disease such as COVID-19, natural antibodies are produced by the immune system to fight the disease. If you get infected again, the immune system will remember how to respond, and quickly destroy the virus. A vaccine can do the same, but without the risk of disease from natural infection. Vaccines work by imitating a bacteria or virus using either mRNA in the case of the COVID-19 vaccine, or a dead or weakened version of the bacteria or virus. The vaccine raises the body’s alarm. It trains the body to recognise and fight the virus. When the body encounters the real-deal virus, it is primed and ready to fight for the body’s health.”

She said South Africa had the mRNA vaccine in the form of the Pfizer vaccine, and the adenoviral vector vaccine in the form of the Johnson & Johnson vaccine.

Why should you get the vaccine?

Dr Potgieter said vaccines are safe and effective, and the most compelling reasons for getting vaccinated are the following:

-To protect yourself from severe disease
-To protect those around you who may be at risk of severe disease
-To restore the social and economic platforms of the country, and the world at large.
She said that while the vaccine does not prevent you from getting COVID-19, it offers better protection against the development of severe disease, and vaccinated people had 50% less chance of spreading the virus.
The most common side effects of the vaccine are the following:
-Pain at the injection site
-Swollen lymph nodes
-Fever
-Fatigue
-Headache
-Myalgia (muscle pain)

“These are indications that the immune system is mounting a response. When it mounts a response, it produces antibodies,” she said.

Answers to commonly asked questions are the following:

1. Can the vaccine alter my DNA?
“No, it goes nowhere near the nucleus of the cell.”

2. What happens when you get COVID in between the first and second doses?
“Some protection is conferred after the first dose, but maximum protection is conferred two weeks after the second dose. Vaccination is still advised.” 

Dr Potgieter said patients who were between vaccinations still show better recovery results than those without.

3. What about natural immunity?
“Natural immunity might confer better protection, but it runs the risk of severe disease. Yes, immunity can be gained through natural immunity, it can be gained through vaccination, and it can certainly be gained by a combination of the two.”

4. What about long-term side effects?
“Serious side effects that cause long-term health problems following any vaccination are very rare, including the COVID-19 vaccination.”

To get the answers to more of your questions, the webinar can be accessed via the following link: https://event.webinarjam.com/go/replay/43/053q6a8vay9a0qa2

News Archive

Well-established root system important for sustainable production in semi-arid grasslands
2015-02-24

Plot layout where production and root studies were done
Photo: Supplied

The importance of a well-established root system for sustainable production in the semi-arid grasslands cannot be over-emphasised.

A study of Prof Hennie Snyman from the Department of Animal and Wildlife and Grassland Sciences at the University of the Free State is of the few studies in which soil-water instead of rainfall has been used to estimate above- and below-ground production of semi-arid grasslands. “In the past, plant ecological studies have concentrated largely on above-ground parts of the grassland ecosystem with less emphasis on root growth. This study is, therefore, one of the few done on root dynamics in drier areas,” said Prof Snyman.

The longevity of grass seeds in the soil seed bank is another aspect that is being investigated at present. This information could provide guidelines in grassland restoration.

“Understanding changes in the hydrological characteristics of grassland ecosystems with degradation is essential when making grassland management decisions in arid and semi-arid areas to ensure sustainable animal production. The impact of grassland degradation on productivity, root production, root/shoot ratios, and water-use efficiency has been quantified for the semi-arid grasslands over the last 35 years. Because of the great impact of sustainable management guidelines on land users, this study will be continuing for many years,” said Prof Snyman.

Water-use efficiency (WUE) is defined as the quantity of above- and/or below-ground plant produced over a given period of time per unit of water evapotranspired. Sampling is done from grassland artificially maintained in three different grassland conditions: good, moderate, and poor.

As much as 86, 89 and 94% of the roots for grasslands in good, moderate and poor conditions respectively occur at a depth of less than 300 mm. Root mass is strongly seasonal with the most active growth taking place during March and April. Root mass appears to be greater than above-ground production for these semi-arid areas, with an increase in roots in relation to above-ground production with grassland degradation. The mean monthly root/shoot ratios for grasslands in good, moderate, and poor conditions are 1.16, 1.11, and 1.37 respectively. Grassland degradation lowered above- and below-ground plant production significantly as well as water-use efficiency. The mean WUE (root production included) was 4.79, 3.54 and 2.47 kg ha -1 mm -1 for grasslands in good, moderate, and poor conditions respectively.

These water-use efficiency observations are among the few that also include root production in their calculations.

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