Strange, how we never used to give vaccinations any thought. It was just something our mothers took care of when we were younger than six years old. You know, polio, tetanus, measles, rotavirus, and others. Until Covid came. Now it is a buzz word, and everyone is an expert.

Free immunisation against 11 vaccine preventable deaths are currently provided in South Africa through the Expanded Programme on Immunisation (EPI). EPI-SA has achieved many successes, with neonatal tetanus being eliminated by 2002; no wild-type poliovirus transmission reported since 1989; more than 60% reduction in hepatitis B virus prevalence in those born after 1995; more than 40% reduction of pneumococcal disease in all age groups since 2009; and a 60% reduction in rotavirus-associated hospitalisations since 2009.

But first, let us look at what vaccines are. Vaccines contain weakened or inactive parts of a particular organism (antigen) that triggers an immune response within the body, so it works by imitating infections in the body, allowing the immune system to develop antibodies against disease. When these antibodies have developed, future infection or complications can be prevented. Newer vaccines contain the blueprint for producing antigens rather than the antigen itself.

There are five common childhood vaccines that infants and young children receive in South Africa:

• Live, weakened vaccines that fight viruses and bacteria. Examples include measles, mumps, rubella and chickenpox vaccines.
• Non-live vaccines also fight viruses and bacteria. Examples include the inactivated polio vaccine, of which one often requires multiple doses of to build/maintain immunity.
• Toxoid vaccines prevent diseases caused by bacteria that produces toxins. The DTaP vaccine contains diphtheria and tetanus toxoids.
• Subunit vaccines includes only parts of a virus/bacteria instead of the entire germ. The pertussis (whooping cough) component of the DTaP is an example.
• Conjugate vaccines fight a type of bacteria that has antigens with an outer coating of sugar-like substances that fools the young child’s immature immune system. Examples are the Haemophilus influenzae type B (Hib) and mRNA COVID-19 vaccines.

It is estimated that between 2 and 3 million vaccine preventable deaths (VPD’s) are averted worldwide through immunisation. But just as we mortal beings never used to give vaccines any thought, we are grateful to the medical staff who adhere to the vaccine storage and handling procedures, ensuring continued protection of us all. Temperature variations outside the recommended range can result in loss of efficacy to the vaccines hence it is very important that these cold chain breaks be taken seriously.

 

The Department of Health recommends all vaccines in South Africa be stored at temperatures between 2 and 8⁰C, as per table below. And of the five South African Health Products Regulatory Authority (SAHPRA) approved Covid 19 vaccines in South Africa, only the Pfizer/BioNTech vaccine is stored at Ultra-low temperatures, but SAHPRA, has approved changes to the storage conditions for the Pfizer Covid-19 vaccine, allowing it to now be stored in a fridge for a month.