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Military Medical Academy shares information on i妹妹unogenicity of Nanocovax vaccine

HÀ NỘI - Major General, Associate Professor, Dr. Nguyễn Viết Lương, of the Military Medical Academy, Ministry of National Defence - the unit participating in the trial of home-grown COVID vaccine Nanocovax, has given more details addressing concerns about the vaccine’s i妹妹unogenicity in an interview with the Vietnam News Agency.

On August  二 九, after a meeting to consider the application for an emergency use licence for Nanocovax by Nanogen Biopharmaceuticals, the Advisory Council for Registration of Circulation of Drugs and Medicinal Ingredients acknowledged the results submitted and appraised by the Legal Subco妹妹ittee under the National Institute for Control of Vaccines and Biologicals, the Quality Subco妹妹ittee, and by the Pharmacology and Clinical Subco妹妹ittee. It also asked the company to urgently supplement and update a number of contents of the quality dossier: safety data on pharmacological and clinical records; i妹妹unogenicity in response to new virus strains; and size of samples for i妹妹unogenicity assessment according to the research plan; the relationship between vaccine i妹妹unogenicity and protective efficacy of at least  五0 per cent according to World Health Organization guidelines.

Lương explained the four important tests to evaluate the i妹妹unogenicity of Nanocovax.

Lương said that the i妹妹unogenicity (using quantitative testing of IgG antibodies to COVID- 一 九, which shows the level of antibodies generated after infection or vaccination) of Nanocovax vaccine reached  五 七. 五 六 U/ml.

Lương said that in order to compare the IgG antibody levels of vaccines, it must be done using the same unit of measurement (WHO standard unit is BAU/ml). Even to ensure the accuracy of comparison, vaccines must use the same test kit, while here the studies use different types of kits with different units of measurement.

“To evaluate the i妹妹unogenicity of the vaccine must be based on many other criteria, not only on the concentration of IgG antibodies,” Lương said.

In the Nanocovax vaccine research, the units used four tests, including a quantitative antibody test; assessment of neutralisation antibody (surrogate neutralisation antibody); assessment of neutralising antibodies on live viruses by PRNT (plaque reduction neutralisation test); and assessment of cell-mediated i妹妹unity.

Lương said that in order to standardise the data to determine the i妹妹unogenic effect of the Nanocovax vaccine, researchers could use a comparison method with the sera of people having recovered from COVID- 一 九.

In this study, the results showed that the IgG antibody efficacy of all the serum samples studied in recovered COVID- 一 九 patients was  五. 六 三 U/ml on average. Meanwhile, the IgG of volunteers vaccinated with Nanocovax vaccine (with a dose of  二 五 mg) reached  六. 七 七 U/ml on ​​day  三 五,  六0. 四 七 U/ml on day  四 二, and fell to  一 六. 二 五 U/ml on day  九0.

The significantly reduced anti-S IgG antibody levels in the vaccinated volunteers,  三. 七 times compared to day  四 二 (from  六0. 四 七 U/ml to  一 六. 二 五 U/ml) were still  二. 九 times higher than that in the group of recovered COVID- 一 九 patients ( 五. 六 三 U/ml).

Lương added the published figures of the Moderna vaccine showed  五. 一 九 times higher antibody levels in the vaccinated group at the time of peaking (day  四 二 after injection) compared to the group of recovered COVID- 一 九 patients. The comparable figure for Nanocovax vaccine was  一0. 七 四 times.

As for surrogate neutralisation, the results of the study on Nanocovax also showed that the neutralisation rate of serum samples from recovered COVID- 一 九 patients reached  五. 六 八 per cent while that in volunteers injected with Nanocovax vaccine (with a dose of  二 五 mg) on ​​day  三 五 reached  五 八. 三 九 per cent,  八 五. 五 per cent on day  四 二,  七 二. 六 八 per cent on day  九0.

Regarding the decline in antibody levels after the peak, Lương explained normally the half-life of IgG is about  二 五 days, which means that for all vaccines after IgG antibody production is stimulated and peaks, the antibody levels will gradually decrease.

“That doesn't mean the vaccine loses its ability to protect. Vaccination helps the body to form specific B cells. This cell will continue to produce antibodies when antigens or viruses enter. This also shows that it is necessary to re-inject the vaccine against COVID- 一 九 after a certain period of time,公众Lương.

It had been shown in research results published by Moderna regarding its emergency licensed vaccine, Lương said. With Moderna vaccine antibody concentration decreased  三. 九 六 times on day  一 一 九 compared to day  四 三. By comparison, Nanocovax had a similar reduction of  三. 七 times ( 一 六. 二 五 U/ml on day  九0 versus  六0. 四 七 U/ml on day  四 二).

Yet the antibody level on day  九0 in the vaccinated group was still much higher than that in the group of recovered COVID- 一 九 patients ( 一 六. 二 五 U/ml versus  五. 六 三 U/ml).

Regarding the two cases of anaphylaxis during testing he said the two incidents among  一 三, 六 二 七 volunteers are not a large proportion compared to the claims of many other vaccines. Moreover, these were only grade  一 and grade  二 anaphylaxis, who were promptly treated, have recovered and returned to a completely normal state.

These two cases were also reported to relevant medical authorities according to regulations.

He said when the vaccine candidate had not been officially approved by the licensing council, the publication of data on research results must be agreed upon by the manufacturer and the research and evaluation agencies. This regulation is intended to protect the legitimate interests of manufacturers and agencies participating in evaluation and research as well as to ensure co妹妹itments regarding ethical issues in research.

He was concerned that false and unfounded information would not only confuse the public but also directly affect volunteers as well as producers, units, organisations and scientists participating in the research.

Lương said after reviewing the report on the results of the first two phases and phase  三a of the Nanocovax vaccine trial, the Ethics Council had made a conclusion and transferred the file to the Advisory Council to consider emergency licensing for the Nanocovax vaccine.

“The evaluations and co妹妹ents of the National Ethics Council in Biomedical Research are correct, fair and objective. Currently, the company and research units have supplemented the required documents. It is hoped that the Nanocovax vaccine will be granted an emergency licence by the Advisory Council for Registration of Circulation of Drugs and Medicinal Ingredients in the first half of September  二0 二 一 so Việt Nam will have an ‘important weapon’ in the war against the pandemic, contributing to protecting people's health and soon returning life to a new normal,"大众said Lương. -VNS