Will herd immunity be effective against COVID-19 | 25th post - Antivirals | DESREM |Mylan | Vaccines | COVID-19 | US | Pfizer | Herd immunity | Remdesivir

Mylan received approval from DCGI for the generic version of Remdesivir, that can be used for treating COVID-19 patients in adults and children with severe illness of the disease. The drug will be available under the brand name DESREM at a price of 4800(INR) which is 70-80% lesser than the branded version.  Gilead sciences for the commercialization of Remdesivir in 127 low and middle-income countries(includes India). Remdesivir is 10^th medicine that has been collaborated with Gilead sciences and their first agreement was signed in the year 2006 for HIV treatment( tenofovir disoproxil fumarate).

Why antivirals are expensive?

Since antivirals are difficult to develop certain factors are to be considered, it includes Bioavailability, Lack of viable drug targets, Lack of the In-vitro model, Market size. Moreover, viruses require a host to live and most of the antibiotics can be used broad spectrum so it reduces the cost but when we consider for antivirals, each viral strain requires an antiviral.

Two COVID-19 vaccines showed prominent results in phase I trials, a DNA vaccine INO-4800 and an mRNA vaccine called BNT162b1. 34 people out of 36 trial participants completed the INO-4800 (94%). Trial participants demonstrated overall immune responses. Six weeks after receiving the two doses of INO-4800, participants were enrolled in 1mg or 2mg dose cohorts. Each participant received 2 doses of INO-4800 four weeks apart. The phase 1 study deals with safety and tolerability. Route of administration: intradermal injection.

40 healthy volunteers aged between18-50 were selected for the trial. 3 participants were excluded from the immune analyses because they tested positive for COVID-19 immune responses. INO-4800 is a nucleic acid-based vaccine that is stable at room temperature for more than a year(it means it doesn’t require to be frozen during transportation or storage), which is a very important factor for mass immunizations. INO-4800 targets the major surface antigen spike protein of SARS-Cov-2. The vaccine can generate balanced antibody and T-cell immune responses. This vaccine candidate is under PhaseII/III trial.

Another mRNA vaccine called BNT162b1 produced antibodies in healthy volunteers. This is a collaborative project between Pfizer and Biontech.  This study enrolled 45 participants who received two doses of the vaccine candidate. Blood levels of these antibodies were found to be more compared to people who recovered from the infection. 4 different mRNA vaccine candidates are been developed by Pfizer and Biontech against COVID-19.

Herd immunity VS COVID-19

Herd immunity is also known as social immunity, this occurs when a large population becomes  immune to a specific  diseases and transmission of disease from a person to a person becomes less. A certain percentage of the population is capable to get a disease and spread it, this is known as threshold proportion, if the proportion of the population that is immune to the disease is greater than a threshold, then the rate of a disease spreading will decline, this is known as herd immunity.

How this can be achieved?

There are generally two ways to achieve herd immunity- Vaccine and natural infection

1. Vaccines- This helps out by creating immunity against the disease without causing illness or complications. Herd immunity protects a certain population who can't be vaccinated like newborn babies or comprised immune systems. Some people may require revaccination as their immune system may be weaker against specific diseases.
2. Natural infection-When sufficient population who are recovered from the disease develop antibodies against infection. A good example to illustrate is 1918 influenza pandemic. Some people who survived this were later immune to swine flu (2009-10).

How to reduce the transmission of COVID-19?

Well, even though many of them may be aware of this, but still due to self-carelessness, the rate of infection may increase.

·        Avoid group gatherings

·        Avoid close contact with an infected or symptomatic person.

·        Maintain social distancing (within about 6 feet, or 2 meters)

·        Wear Face masks in order to reduce close contact in public places.

Many people may have a common question, whether if I follow those precautionary measures, will  I won't get infected. The answer may be no, it depends upon nature.

 

"By discovering nature, we discover ourselves"