Cyprus International University Faculty of Medicine Lecturer Asst. Umut Altunç has given some answers regarding the efficacy and safety of the Covid-19 vaccine. He has explained, inter alia, about the Chinese vaccine Sinovac, which will be the main vaccine available for North Cyprus from Turkey from 11 December. It was reported that supplies of AstraZeneca and Pfizer/BioNTech vaccines will also be available from south Cyprus from January.
This article focuses on the Sinovac vaccine.
Sinovac Dead vaccine
On paper, one of Sinovac’s main advantages is that it can be stored in a standard refrigerator at 2-8 degrees Celsius, like the Oxford vaccine.
To produce these vaccines, the Covid-19 virus is inactivated by chemical (formaldehyde etc.), heat, cold or similar methods. In addition, adjuvant substances such as Aluminum salts are added to the vaccine, which will help the dead virus stimulate the immune response . In this way, the immune system, which encounters the dead virus, does not cause the disease when it develops antibodies against the virus. Since each vaccine is developed in individual cell cultures (with a technology similar to a flu vaccine, chicken egg-like environments ), its costs are higher than other vaccines and its production takes time. While it can be stored in degrees for up to 3 years, it is recommended to take two doses with an interval of 14 days.
The Chinese Sinovac company vaccine is prepared using the oldest and best known method . It is anticipated that the efficacy of the vaccines produced in a similar way to the flu vaccines, which are produced in millions of doses every year, will also be limited . But hundreds of thousands of doses in China, Turkey and Brazil, although it has been applied in the tens of thousands of doses of vaccine efficacy and side effects associated with medical reports have not yet been published. According to a study reported in Indonesia on December 6, 2020, antibody responses of up to 97% were observed after vaccination . The possible side effects of the so-called auxiliary substances and the chemical means by which they are inactivated have not been reported in detail. The long-term protection or side effects of vaccines are not yet known.
According to online publication Medshadow.org, Sinovac opened Phase III trials of its vaccine candidate, CoronaVac, in July. It is already being used with emergency approval for high risk individuals in China. The earlier trials showed that about a third of patients experienced adverse effects similar to those in other vaccine candidates like injection site pain, fever, and fatigue, but the study included few details about more specific symptoms like nausea, headaches, and vomiting.
The vaccine is yet to finish its late-stage trials.
BBC News reported on Wednesday that people with a history of significant allergic reactions should not have the Pfizer/BioNTech Covid jab, regulators say.
This warning came after two NHS workers had allergic reactions on Tuesday.
The advice applies to those who have had reactions to medicines, food or vaccines, the Medicines and Healthcare products Regulatory Agency said.
The two people had a reaction shortly after having the new jab, had treatment and are both fine now.
They are understood to have had an anaphylactoid reaction, which tends to involve a skin rash, breathlessness and sometimes a drop in blood pressure. This is not the same as anaphylaxis which can be fatal.
Both NHS workers have a history of serious allergies and carry adrenaline pens around with them.
Potential serious side-effects of Sinovac are as yet unreported.
Yeniduzen, Medshadow.org., BBC News