The safety of vaccines

Posted on 25 March 2021

Overwhelming scientific evidence exists that vaccination is the best defence against serious infections.

Immunisation is a global health success story, saving millions of lives every year, according to the World Health Organization (WHO). Vaccines reduce your risk of getting sick by working with your body’s natural defences to build protection.

Vaccines are already available to prevent more than 25 life-threatening diseases, helping you to live a longer, healthier life. In fact, immunisation programmes currently prevent up to 3 million deaths every year.

Today, 86% of the world’s children receive essential, lifesaving vaccines. This protects them and their communities against a range of infectious diseases, including measles, diphtheria, tetanus, pertussis (whooping cough), hepatitis B and polio.

Through vaccination, smallpox has been eradicated and polio is on the verge of being defeated – the number of children paralysed by polio has been reduced by 99.9% worldwide over the past three decades.

The WHO also studies influenza trends every year to work out which strains are emerging and should be included in the next season’s flu vaccine. It’s also joined innovative partnerships to help lead major cholera and yellow fever vaccination campaigns. Similar partnerships have produced effective vaccines against meningitis, pneumonia and diarrhoea, as well as the world’s first-ever malaria vaccine.

In 2014-16 the Ebola epidemic in West Africa killed more than 11 000 people. This epidemic triggered the first human trials of a vaccine against the disease and prompted changes in the way the world responds to outbreaks.

To tackle the threat of Ebola, the priorities were to fund vaccine discovery, fast-track clinical trials, hasten regulatory approvals and enable manufacturers to produce and roll out a vaccine quickly. It took only 10 months from early testing to trials of the Ebola vaccine in Guinea in 2016 – a speed unprecedented at the time.

In 2010, an affordable meningococcal vaccine was introduced in response to widespread meningitis epidemics in sub-Saharan Africa. More than 300 million people living in the meningitis belt countries have since been vaccinated, resulting in a dramatic decline in deaths – and all but ridding these countries of this major cause of deadly epidemics.

Vaccines continue to prove critical in preventing and controlling infectious-disease outbreaks and they are and will be a vital tool in the battle against COVID-19.

All vaccines go through a rigorous, multi-stage testing process, including large trials that involve tens of thousands of people. These trials, which include people at high risk for a specific disease, are designed to identify any common side-effects or other safety concerns.

Once a clinical trial shows that a vaccine is safe and effective, a series of independent reviews of the efficacy and safety evidence is required. This includes regulatory review and approval in the country where the vaccine is manufactured. Only then will the WHO consider a vaccine product for prequalification.

An external panel of experts convened by WHO then analyses the results from clinical trials, along with evidence on the disease, age groups affected, risk factors for disease, and other information. The panel recommends whether and how the vaccines should be used.

Vaccines remain the safest, most cost-effective protection against disease and are powerful weapons in the battle against the COVID-19 pandemic. As Dr Gerrit de Villiers, Chief Clinical Officer, Mediclinic Southern Africa says, ‘vaccination is not a treatment or cure for someone who is already infected or sick. Instead, it is a strategy to help train our immune system to be better equipped to deal with the infection in the future, so that infection or disease is prevented. After all, prevention is better than cure.’

Remember, even after being vaccinated against COVID-19, you must continue to wear a mask in public, practise physical distancing and maintain good hand hygiene.


Source: World Health Organization

Published in Covid-19

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