The Central Drugs Standard Control Organization has allowed the use of anti-Covid-19 drug ‘ Molnupiravir’ (tablet) and anti- Covid-19 vaccines ‘Covavax’ and ‘Corbevax’ for emergency use with certain conditions.

Molnupiravir: Oral Antiviral Drug

• Drug :- Molnupiravir
• Developers :- US based firms Ridgeback Biotherapeutics and Merck.
• Mandate :- It has been cleared for the treatment of adult patients with Covid-19 “who have a high risk of progression of the disease”.
• Working :- It works by introducing errors into the virus’s genetic code, which prevents replication.
• Dose:- Molnupiravir comes in 200 mg pills; the recommendation in India is for 800 mg twice daily for 5 days.
• Manufacturers :- 13 Indian drug makers Dr Reddy’s, Natco, MSN, Hetero, Optimus, Aurobindo Pharma, Mylan, Cipla, Sun Pharma, Torrent, BDR Stride and Pune based Emcure.
• Efficacy:-

1. UK:- Cleared molnupiravir on December 4, as it has been found “safe and effective”.
2. US:- Cleared on December 23, did not authorise it for use for longer than five consecutive days, or in patients younger than 18.
3. India :- Recommended for treatment of adult Covid patients with oxygen level over 93%, and who have a high risk of progression of the disease

Corbevax :- Protein Sub-unit Vaccine

• Vaccine :- Corbevax,
• Developers :- The antigenic parts of the virus have been developed by Texas Children’s Hospital Centre for Vaccine Development and in-licensed from BCM (Baylor College of Medicine) Ventures
• Mandate :- Vaccine to be used under emergency use authorisation
• Working :- Corbevax is a protein sub-unit vaccine, which means that instead of the whole virus, it uses fragments of it to trigger an immune response. In this case, the subunit vaccine contains a harmless S protein. Once the immune system recognises the protein, it produced antibodies to fight a real infection when it happens.
• Manufacturer :- Biological E Limited, Hyderabad. Biological E plans to begin production at 75 million doses per month, and anticipates reaching 100+ million doses per month from February.
• EFFICACY:-

1. Biological E has completed Phase III trials on more than 3,000 subjects at 33 study sites across India.
2. It said, neutralising antibody titres against Delta strain indicates a vaccine effectiveness of more than 80% for the prevention of symptomatic infections based on published studies.
3. In the Phase 3 active comparator clinical trials conducted with an end point of immunogenic superiority, Corbevax demonstrated superior immune response in comparison with Covishield vaccine when assessed for Neutralizing Antibody (nAb) Geometric Mean Titers (CMT) against the Ancestral-Wuhan strain and the globally dominant Delta variant.

Covavax:- Recombinant Nanoparticle Vaccine

• Vaccine:- Covavax
• Developers :- Novavax, USA
• Mandate :- On December 20, the WHO has issued Emergency Use Listing to the vaccine.
• Working :- Covavax is a protein sub-unit vaccine, but uses recombinant nanoparticle technology. Harmless copies of the spike protein are grown in insect cells. The protein is then extracted and assembled into virus-like nanoparticles. Novavax has used an immune-boosting compound (adjuvant).
• Manufacturer :- Serum Institute of India (SII)
• Efficacy :-

1. SII has said the vaccine has been evaluated in two Phase 3 trials
2. In the UK an efficacy of 96.4% against the original virus strain, 86.3% against Alpha and overall efficacy of 89.7%.
3. The PREVENT-19 trial in the US and Mexico has demonstrated 100% protection against moderate and severe disease and overall efficacy of 90.4%.
4. On December 2, 2021 Novavax announced that patients who got a third (6-month booster) dose of this vaccine produced “robust anti-Spike IgG responses” following a booster dose at Day 189.

“Neutralization titers increased 4.3-fold overall compared to the peak response seen after the primary vaccination series,” it said.