NIH says Covaxin effective against Delta, Alpha variants of Covid-19

A research collaboration between India and the USA initiated in 2019 has made Covaxin, the indigenous Covid-19 vaccine, more effective against the coronavirus infection.

An adjuvant - Alhydroxiquim-II, developed by a Kansas based bio-tech company ViroVax LLC has enhanced the efficacy of Covaxin, according to US's National Institutes of Health (NIH) which noted that Covaxin was found be generating antibodies effectively neutralising the B.1.1.7 (Alpha) and B.1.617 (Delta) variants of SARS-CoV-2.

Adjuvants are substances formulated as part of a vaccine to boost the immune responses and thus enhance a vaccine’s effectiveness.

Read more: Pre-submission meet held, Covaxin's 'Rolling Data' to start in July: WHO

After the health crisis it has caused in India over the last three months, the Delta variant is spreading globally, becoming the most potent Covid-19 threat currently in several countries including the US and the UK.

“Ending a global pandemic requires a global response,” said Anthony S Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID), a part of NIH - the US medical research agency.

"I am pleased that a novel vaccine adjuvant developed in the United States with NIAID support is part of an efficacious Covid-19 vaccine available to people in India,” the renowned scientist said, according to a NIH news release on Tuesday.

Alhydroxiquim-II travels to lymph nodes, where the small molecule detaches from alum and activates two cellular receptors - TLR7 and TLR8, which play a vital role in the immune response to viruses. Alhydroxiquim-II is the first adjuvant in an authorised vaccine against an infectious disease to activate TLR7 and TLR8. In addition, the alum in Alhydroxiquim-II stimulates the immune system to search for an invading pathogen.

“Molecules that activate TLR receptors stimulate the immune system powerfully, but the side effects of Alhydroxiquim-II are mild. This is because, after Covaxin is injected, the adjuvant travels directly to nearby lymph nodes, which contain white blood cells that play an essential role in identifying pathogens and fighting infections. Consequently, only a small amount of Alhydroxiquim-II is needed in each dose of vaccine, and the adjuvant does not circulate throughout the body, thereby averting more widespread inflammation and undesirable side effects,” NIH said.

“Results from two studies of blood serum from people who had received Covaxin suggest that the vaccine generates antibodies that effectively neutralize the B.1.1.7 (Alpha) and B.1.617 (Delta) variants of SARS-CoV-2, first identified in the United Kingdom and India, respectively,” NIH said, citing the research by ICMR-NIV, Bharat Biotech investigators.

The NIAID Adjuvant Program has been supporting the research of Sunil David, M.D., Ph.D., founder and CEO of ViroVax―since 2009. His work focused on searching for novel molecules that activate innate immune receptors and developing them as vaccine adjuvants.

The collaboration between Dr David and Covaxin maker Bharat Biotech International Limited was initiated during a 2019 meeting in India coordinated by the NIAID Office of Global Research under the auspices of Indo-US Vaccine Action Program.

A delegation of NIAID-funded adjuvant investigators including Dr David and NIAID members had visited four leading biotechnology companies to learn about their work and discuss potential collaborations.

The delegation had also attended a consultation in New Delhi hosted by the National Institute of Immunology.

“Among the scientific collaborations sparked by these activities, Bharat Biotech signed a licensing agreement with Dr David to use Alhydroxiquim-II in their candidate vaccines. This license was expanded during the Covid-19 pandemic to include Covaxin. The company conducted extensive safety studies of Alhydroxiquim-II and undertook the complex process of scaling up production of the adjuvant under Good Manufacturing Practice standards,” NIH release said.

Covaxin, developed in collaboration with the Indian Council of Medical Research-National Institute of Virology, has received Emergency Use Authorization in over a dozen countries. Bharat Biotech expects to reach a production number of one billion Covaxin doses annually by 2021-end.