Two studies published recently explored the effects of heterologous boosters after receiving two doses of Koxing vaccine. The Brazilian study published at Lancet explored the effects of homologous and heterologous reinforcement, while the Thai study on medrxiv only explored heterologous reinforcement.
Hokkaido University's Master of Neuroscience, a senior medical consultant at Sheng Nuo, and Weibo Science Popularization University V Zhuang Shili and interpreted the two studies separately.
Zhuang Shilihe: Lancet published the results of a Phase IV clinical study in Brazil that explored homologous and heterologous enhancement after two doses of Coxing vaccine.
The study recruited 1239 volunteers, including 18-60 years old (51%) and 61 years old and older (49%), who had received two doses of the Koxing vaccine six months earlier.
The volunteers were divided into four groups for a randomized, single-blind trial in which the booster (third dose) consisted of 2 adenovirus vector vaccines, 1 mRNA vaccine, and 1 inactivated vaccine.
They are: Johnson & Johnson Vaccine (Ad26.COV2-S), Pfizer Vaccine (BNT162b2), Oxford Vaccine (ChAdOx1 nCoV-19), and CoronaVac Vaccine. The researchers took blood samples before the third dose (Day 1) and at day 28 (Day28).
Just look at the results.
Within 7 days of receiving the third injection, local adverse reactions are most commonly pain and headache at the injection site.
Pain ratio at the injection site: Johnson & Johnson vaccine 60%, Pfizer vaccine 76%, Oxford vaccine 63%, Cosh vaccine 39%.
Headache ratio: Johnson & Johnson vaccine 45%, Pfizer vaccine 30%, Oxford vaccine 49%, Cosh vaccine 20%.
The most common systemic adverse effects were fever and chills, at a rate of 11% & 26% Johnson & Johnson vaccine, 2% & 9% Pfizer vaccine, Oxford vaccine 14% & 33%, and Coshing vaccine 1% & 7%, respectively.
In terms of safety, the overall tolerance of the reinforcing needle is good.
The most important is the immunogenicity outcome, which was tested for a very large number of indicators of immunogenicity in this Phase IV clinical trial in Brazil, including anti-S protein IgG, anti-N protein IgG, anti-RBD IgG, pseudoviral neutralization test (IC50), and live virus neutralization antibody levels against Delta and Omicron.
Let's look at the more practical neutralizing antibody levels.
In the pseudovirus and in the trial, the average geometric titers and growth factors of Day 1 and Day 28 were:
- Johnson & Johnson vaccine: 311844, 61 times
- Pfizer vaccine: 254326, 176 times
- Oxford vaccine: 252137, 85 times
- Coshing vaccine: 30136, 7 times
In the neutralization trial of live viruses, the neutralizing antibody titers facing Delta on Day 1 and Day 2 were:
- Johnson & Johnson Vaccine: 12677
- Pfizer vaccine: 121653
- Oxford vaccine: 12710
- Coxing vaccine: 1361
The data for facing Omicron are:
- Johnson & Johnson Vaccine: 10138
- Pfizer vaccine: 10223
- Oxford vaccine: 10102
- Cosh vaccine: 1117
Lancet's study shows that all four of these vaccines are safe to use as a third dose, while heterologous enhancement exhibits a more robust immune response.
The study at Chulalongkorn University in Thailand, published on medrxiv, explored heterologous enhancement after receiving two doses of the Koxing vaccine.
The study enrolled 224 volunteers (median age 41 years) who had received two doses of the Koxing vaccine six months earlier for xogenous boosting with inactivated vaccines (BBIBP-Sinopharm Beijing), viral vector vaccines (AZD1222-Oxford vaccines), and mRNA vaccines (BNT162B2-Pfizer vaccines and mRNA-1273-Moderna vaccines).
In terms of safety, the overall tolerance of the four heterologous enhancements was good, and the induced adverse reactions were mild to moderate. In terms of immunogenicity, the most neutralizing levels and T cell responses to Delta and Omicron were the Moderna vaccine, followed by the Pfizer vaccine, the Oxford vaccine and the Sinopharm Beijing vaccine.
In the live virus neutralization trial, after 6 months of two-shot Koxing vaccination, the neutralizing antibody was undetectable to almost all vaccinators facing Delta and Omicron (titer<20).
After receiving the booster needle, the neutralizing antibody levels facing Delta were:
- Sinopharm Beijing: 69
- Oxford: 1003
- Pfizer: 1285
-Modern:2168
Neutralizing antibody levels against Omicron are:
- Sinopharm Beijing: 24
- Oxford: 250
- Pfizer: 277
-Modern:512
This study is corroborated by other previous studies. The researchers believe that all four booster vaccines significantly increased the levels of binding and neutralizing antibodies after the two-shot Koxing vaccination and provided a reference for subsequent vaccine strategies.
Curated: Ground cat
Executive Producer: Gyouza