The company recently withdrew the vaccine globally citing low demand and availability of newer versions.
Kenya received more than 1.3 million doses of the AstraZeneca vaccine and vaccinated more than 10 million people using the AstraZeneca, Moderna, Johnson & Johnson, Pfizer and Sinopharm vaccines.
Researchers at the Kemri Wellcome Trust Research Programme - Kilifi tested the Oxford-AstraZeneca vaccine in Kenya between October 2020 and August 2021.
They recruited and randomly assigned 400 healthy adults the Covid vaccine or control rabies vaccine to test its safety and whether it produces immune response.
The researchers say although they reported many adverse effects from participants who received the Covid vaccine, none were severe.
“Local and systemic adverse events were self-limiting and mild or moderate in nature,” the researchers said in a study they published in the Wellcome Open Research journal.
“Systemic adverse reactions reported within seven days after each vaccination were headache, myalgia (muscle pain), fatigue, arthralgia (joint pains), chills, malaise, nausea and fever. Headache was the most common systemic reaction,” they said.
Systemic effects are those occurring in tissues distant from the injection site.
The researchers said although severe adverse events have been reported in larger studies, including thrombotic events and myositis (inflammation and degeneration of muscle tissue) the study in Kenya was underpowered to detect rare events.
“Our study sample size precluded assessment of rare adverse events such as thrombosis with thrombocytopenia syndrome (TTS) that has been observed in populations in Europe following adenovirus-vectored Covid-19 vaccines. ChAdOx1 nCoV-19 has been used in many countries in Africa, but we are aware of no reports of TTS associated with its use on the continent,” they said. Their study was published late last year.
Two weeks ago, the AstraZeneca wrote in a legal document submitted to the UK High Court that: “It is admitted that the AstraZeneca vaccine can, in very rare cases, cause TTS. The causal mechanism is not known.”
The company is facing a class action suit in the UK.
TTS causes people to have blood clots and a low blood platelet count. It can cause long-term disability and death. Symptoms of TTS include severe, persistent headache that do not improve with regular painkillers, blurred vision, confusion or seizure, weakness of face or limbs, shortness of breath or chest pain, severe abdominal pain, leg swelling and unexplained pin-prick rash or bruising away from the injection site.
The vaccine was given as a two-dose regime up to 12 weeks apart.
“Ongoing pharmacovigilance is required, however the data seen in Kenya do not suggest a difference adverse event profile from that seen elsewhere,” the researchers in Kenya added.
Their study was titled "Safety and immunogenicity of ChAdOx1 nCoV-19 (AZD1222) vaccine in adults in Kenya."
Last week, AstraZeneca said it had decided to withdraw its Covid-19 vaccine globally due to a "surplus of available updated vaccines" for the new variants of the virus.
The company said there is a variety of newer vaccines available that have been adapted to target Covid-19 variants leading to the decline in demand for AstraZeneca.
The vaccine was authorised for use in those aged 18 and older, delivered as two injections, usually into the muscle of the upper arm, about three months apart.
In the race to lift the world out of pandemic lockdowns, the Covid-19 vaccine was developed by scientists at the University of Oxford in record time.
In a statement, AstraZeneca said: "According to independent estimates, over 6.5 million lives were saved in the first year of use alone."
"Our efforts have been recognised by governments around the world and are widely regarded as being a critical component of ending the global pandemic," it said.
Africa was among the largest consumers of the drugs with Kenya receiving more than 1.02 million doses of the vaccine in 2021.
