Health experts dealing with covid-19 pandemic have called upon Ugandan Nationals to stop being sceptical about the current vaccines available in the market urging to go and get vaccinated.

The scientists assured Ugandans about the safety of the vaccines saying all vaccine types that are available in the market are developed using the approved scientific procedure observed by scientists and pharmaceutical industries across the globe.

Dr Catherine Kyobutungi a resource person at African Population and Health Research Center (APHRC) based in Nairobi explaining about the tools, processes and challenges encountered while developing vaccines to a group of science journalists during the monthly biocafe noted that all the current covid-19 vaccines types available are safe for use.

Technologies used to develop covid-19 vaccines

Dr Kyobutungi contends that health scientists have over the years been using three types of technologies to develop vaccines.

The three main approaches to designing a vaccine though their differences lie in whether scientists use a whole virus or bacterium; just the parts of the germ that triggers the immune system; or a genetic material that provides the instructions for making specific proteins and not the whole virus.

They include the whole-microbe approach where scientists develop the inactivated vaccine, the live attenuated vaccine and viral vector vaccine

The first one is where a disease carrying virus is inactivated using chemicals through heat or radiation. Vaccines for polio and flue are made using this method where two or three dozes have to be administered.

The second type is the Live-attenuated vaccine where scientists use a living but weakened version of the virus to develop the vaccine. Measles, mumps and rubella (MMR) vaccine and the chickenpox are examples of this type of vaccine.

This approach uses similar technology to the inactivated vaccine and can be manufactured at scale.

However, vaccines like this may not be suitable for people with compromised immune systems

The third vaccine type under this technology is viral vector vaccine where scientists use a safe virus to deliver specific sub-parts called proteins of the germ of interest so that it can trigger an immune response without causing disease.

To do this, the instructions for making particular parts of the pathogen of interest are inserted into a safe virus. The safe virus then serves as a platform or vector to deliver the protein into the body where the protein triggers the immune response.

This type of vaccine include the Ebola vaccine and this type can be developed rapidly

The second technology used is the A subunit approach and this is where scientists use a very specific parts of a virus or bacterium that the immune system needs to recognize. It doesn't contain the whole microbe or use a safe virus as a vector.

The subunits may be proteins or sugars. Most of the vaccines on the childhood schedule are subunit vaccines, protecting people from diseases such as whooping cough, tetanus, diphtheria and meningococcal meningitis

The last approach is the genetic approach where nucleic acid vaccines are developed

Dr Kyobutungi explained that unlike vaccine approaches that use either a weakened or dead whole microbe or parts of one, a nucleic acid vaccine just uses a section of genetic material that provides the instructions for specific proteins, not the whole microbe.

“DNA and RNA are the instructions our cells use to make proteins. In our cells, DNA is first turned into messenger RNA, which is then used as the blueprint to make specific proteins. A nucleic acid vaccine delivers a specific set of instructions to our cells, either as DNA or mRNA, for them to make the specific protein that we want our immune system to recognize and respond to,” she noted

his she said is a new way of developing vaccines and  before the COVID-19 pandemic, none had yet been through the full approvals process for use in humans, though some DNA vaccines, including for particular cancers, were undergoing human trials.

Due to the pandemic, research in this area has progressed very fast and some mRNA vaccines for COVID-19 are getting emergency use authorization, which means they can now be given to people beyond using them only in clinical trials.

Dr Kobutungi contends that once people go and get vaccinated, this is of advantage because it creates immunity within the body system not to cause severe effects once infected with the virus.

Approved vaccines

Dr Lawrence Mugihsa from College of Veterinary Medicine, Animal Resources and BioSecurity (CoVAB) noted that so far there are 21 vaccines approved by World health organisation for use mainly developed by the following countries  China, Russia, USA,  Cuba,  Iran, India , UK , Netherlands and Taiwan and some are develop out of joint trials

The most common type in the market are AstraZeneca, Pfizer, Moderna, Sputhink V and Siopharm which the scientists say all serve the same purpose and are safe for use.

The statistical figure by the beginning of October indicated that 42.8 of the world population has received at least one doze, 5.86 billion dozes have so been administered and 29.9 million are administered every day. Only 1.9% of the population in low income countries have received at least 1 dose.

Africa for now is not taking part in vaccine development due to the high costs involved and lack of appropriate facilities is a hindrance.

Some of the pandemics

The WHO estimates that vaccines for various viruses and diseases have prevented 10m deaths between 2010 and 2015. The shortest period of vaccine development and distribution has been 4 months

Some of pandemics include Spanish flue which caused 40m-50m deaths and the vaccine was developed in 25 years.

Another pandemic are H3N2 Hong Kong flue and H2N2 Asian flu that killed 1m people and the vaccine was developed in 5 months.

SARS caused 774 deaths in 2003 and the vaccine was developed after 17 years and Ebola caused 11,300 deaths between 1976 -2019 which is still ongoing and the vaccine was developed in 43 years.

HIV/Aids killed 25-35million people in 1981 which is still ongoing and vaccine is ongoing in a duration of 39 years so far

HINI Swine flu caused 575,400 deaths by 2009 and vaccine was developed in 6 months, MERS killed 858 people and vaccine was developed in 8 years

Now we have Corona-19 virus which has so far killed 1.54 M and it is still ongoing with the vaccine developed in 11 months.