A recent study provided a notable result that spike-protein neutralising antibodies were considerably greater with mixed vaccination rather than receiving the same vaccine.

AIG Hospitals, one of India's major tertiary care institutions, in collaboration with researchers from the Asian Healthcare Foundation, launched a pilot study to ascertain the safety profile of combining Covishield with Covaxin and to monitor the antibody response.

The research examined for SARS-CoV-2 antibodies 330 healthy individuals who were not vaccinated and had no history of COVID infection. 44 (13%) of these 330 subjects were seronegative, meaning they lacked COVID-related antibodies.

For the study, 2 four-groups of 44 people were formed.

• Group 1: Covishield initial dose + Covishield second dose
• Group 2: Initial Covaxin dose + Second Covaxin dose

Groups 1 and 2 were homologous vaccination groups that received the same vaccine and had their antibody titres tested.

• Group 3: Initial Covishield dose + Second Covaxin dose
• Group 4: Initial Covaxin dose + Second Covishield dose

Groups 3 and 4 were heterogeneous vaccination groups, in which several vaccines were administered and antibody titers were determined.

All 44 individuals were tracked for 60 days to see whether any adverse effects occurred. The research demonstrated unequivocally that combining vaccinations is completely safe since none of the individuals had an adverse reaction. The study's most notable result was that the spike-protein neutralising antibodies were considerably greater in the mixed vaccination groups than in the same-vaccine groups.

Antibodies that neutralise spike-proteins are those that destroy the virus and lower its overall infectivity.

The study's findings indicate that combining COVID vaccinations (Covishield and Covaxin) increases antibody response and is also safe.

AIG Hospitals has sent the research's data to the ICMR (Indian Council for Medical Research) for use as a reference study in determining the "prevention" dosages beginning January 10.

Omicron: A new study provides the most effective method of protection

Around six months after receiving the second dose of a COVID-19 vaccination, vaccine efficacy declines to 52% against Omicron. However, a booster dose significantly boosts protection and reduces the likelihood of hospitalisation. Recent research reveals that vaccination with a booster dose provides 88 per cent protection against hospitalisation due to infection with the Omicron COVID-19 strain.

Recent findings were reported in a study by the UK Health Security Agency (UKSHA). Around six months after receiving the second dose of a COVID-19 vaccination, the vaccine's efficacy against Omicron reduces to 52%, according to Eric Topol, professor of molecular medicine and head of the Scripps Research Translational Institute in the United States. However, a booster dosage significantly boosts immunity and decreases the risk of hospitalisation for COVID-19 infection.

That is a significant increase in protection for the third dose vaccination compared to hospitalisation for Omicron infection. Vaccine efficacy rose from 52% after the first two doses to 88% after the third dosage. It's quite remarkable that vaccines directed against the ancestral strain spike from two years ago, against the virus that has evolved through over 290 million confirmed cases, and now against the hyper-mutated Omicron, have maintained efficacy of nearly 90% against severe disease with a third shot.

How the research was carried out

Two studies were listed in the UKHSA report that explored the link between two COVID variants (Omicron and Delta) with vaccination status and hospitalisation risk.

The first research analysed roughly half a million Omicron incidences across all age groups, while the second study analysed a smaller dataset and is limited to those aged 18 and older.

The second research validates a prior result that Omicron had a lower overall risk of hospitalisation than the Delta variation.

Both trials revealed a significant decrease in the probability of hospitalisation for Omicron patients after three vaccination doses compared to individuals who are not immunised.

Despite the anticipated decrease in hospitalisation risk and maintained immunisation efficacy against hospitalisation, the research authors cautioned that high numbers of hospital admissions may still occur. Omicron's risk of hospitalisation from emergency departments was roughly one-third that of Delta.

Disclaimer- The views and opinions expressed in this article are those of the author's and do not necessarily reflect the official policy or position of M3 India.

The author is a practising super specialist from New Delhi.