Covishield, Covaxin, Sputnik V: Know the differences, similarities in parameters of three COVID-19 vaccines

India has two home-grown vaccines approved and deployed in current vaccination drive and a third one from Russia approved and awaiting delivery.  The registration process for those in 18-45 age group began on the government’s CoWIN platform on April 28 for vaccination is set to begin on May 1. Currently, the government-sponsored drive covers only those above 45 years at designated vaccination sites.

India is trying to accelerate its massive vaccination programme in the middle of a devastating second Covid-19 wave, the government has an also allowed sales of vaccines to private players. In a 'philanthropic gesture', the Serum Institute of India on Wednesday announced that it would sell its's COVID-19 vaccine 'Covishield' for Rs 300 to state governments, instead of the Rs 400 they had earlier decided.

Meanwhile, Covaxin, India's home-grown COVID-19 vaccine, has been found to neutralise the 617 variant of the deadly virus, White House chief medical adviser and America's top pandemic expert Dr Anthony Fauci said in Washington. The New York Times on Tuesday said Covaxin works by teaching the immune system to make antibodies against the SARS-CoV-2 coronavirus. The antibodies attach to viral proteins, such as the so-called spike proteins that stud its surface.

Both. Covaxin and Covishield are available to Indian citizens for free at government centres and at Rs 250 in private hospitals. Imported, fully ready-to-use foreign vaccines like Sputnik V will also become available in the open market post Saturday, May 1, . The Indian consumers will have to buy their vaccines once private sales begin or states buy stocks to vaccinate these people.

Here is a comparison between Covishield, Covaxin, and Sputnik V:

Vaccine	Type of Vaccine	Dosage and time gap between doses	Storage and expiry	Price in INR (Rs)
AstraZeneca (Covishield from SII - Pune)	Viral Vector	2 injections, 12-week gap	2 to 8 Deg C, 6 months	For govt: Rs 300 per dose to states and Rs 600 per dose to private hospitals For citizens: Rs 250 in private hospitals and free at government centres
CoVaxin (Bharat Biotech, Hyderabad)	Inactivated Virus	2 injections, 4-8 week gap	2 to 8 Deg C	For govt: Rs 600 per dose for state governments and Rs 1,200 per dose for private hospitals For citizens: Rs 250 in private hospitals and free at government centres
Sputnik V (Gamaleya - Russia  & Dr Reddy's)	Viral Vector	2 injections; 21 days to 3 months	-18.55 Deg C (liquid form) and 2 to 8 Deg C (dry form)	Not yet officially declared for India. Globally priced at $10 (approx Rs 750) per dose.

Sputnik uses two different vectors (carriers) for its vaccine, therefore its two doses are different. Both must be taken as prescribed. As for AstraZeneca's Covishield and Bharat Biotech's Covaxin, epidemic experts and virologist say that no two different vaccines must be mixed and matched for the two doses. 

For vaccines requiring multiple doses, the dose usually induces an immune response about three weeks later, but it can take up to eight weeks or longer for the antibodies to mature and become fully functional.

So even after taking the two doses as prescribed, people must continue with their COVID-19 safety protocol of washing hands with soap and water, social distancing, and masking up - apart from the other SOPs that help us stay safe.

This is only for your information, kindly take the advice of your doctor for medicines, exercises and so on.     

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The difference between vaccine efficacy and vaccine effectiveness – and why it matters

With India’s Covid-19 vaccination campaign proceeding, two terms that sound similar are prone to misinterpretation: vaccine efficacy and vaccine effectiveness. The dictionary meanings of these terms are different from the way they are used in scientific discourse. Understanding them could help readers make informed decisions when they are getting vaccinated.

Vaccine efficacy

Many people interpret vaccine efficacy to mean the percentage of people who would not get the disease after vaccination. Sometimes, it is also interpreted as the percent of possibility that a vaccinated person would be protected from the disease. However, it is not as straightforward.

To understand vaccine efficacy, one has to first know a little bit about randomised controlled trials, a type of research design, commonly used for clinical trials – in this case, for Covid-19 vaccines. In RCTs, the study participants are randomly assigned into two comparable groups. In one, the experimental group, the actual vaccine is administered. The other, the control group, gets a placebo – a neutral, unharmful substance that is not a vaccine.

The process takes place in optimal conditions, which means that it occurs in an environment that is scientifically controlled and is similar for both experimental and control groups. If the outcome in the experimental group, in statistical terms, is significantly better than the outcome in the control group, the vaccine would be called efficacious.

Interpreting vaccine efficacy

The efficacy of Covid-19 vaccines is mentioned in percentages. The way it is calculated and interpreted is a little more complicated.

If, for instance, a vaccine is 90% efficacious, this means that out of the total number of people enrolled in the vaccine trial, if about 1% of the people in the control group (who received the placebo instead of the vaccine) get symptomatic Covid-19, only 0.1% of those in the experimental group (who received the vaccine) would get symptomatic Covid-19.

Efficacy is a comparative measure of vaccine performance and not its absolute measure. Ninety per cent efficacy simply means that if 10 people out of 100 unvaccinated people normally get symptomatic disease, only one out of 100 vaccinated ones would get it. The formula used to measure vaccine efficacy is 100 x [1 - (attack rate in the experimental group divided by attack rate in the control group)]. In our example, it would be 100 x [1 - (1/10)] = 90%.

India is currently using two vaccines for Covid-19: Covishield, produced by the Serum Institute of India, and Covaxin, produced by Bharat Biotech. Based on the first clinical trial results, Covishield was 90% efficacious in preventing symptomatic Covid-19 after two doses as per the prescribed schedule, while Covaxin is 81% efficacious.

However, the Covishield vaccine efficacy has been lowered over time and the latest results show that it is 76% efficacious against symptomatic Covid-19. Efficacy rates change based on the gap between the first and the second dose of the vaccine. India has changed the schedule of Covishield vaccine – the recommended gap between the two doses is now six-eight weeks, up from four weeks earlier.

The Sputnik V vaccine, being manufactured in India by Dr Reddy’s Laboratories, is due to be used in the country soon. Its efficacy is said to be 91.6%, next only to the vaccines by Pfizer-BioNTech and Moderna, the two vaccines that are not currently used in India.

Efficacy in what terms?

Vaccines are primarily aimed at preventing a disease due to infection and in turn, its spread. They stimulate an immune response within the body without causing a real infection, which in turn protects the body should there be a real infection later. Therefore, efficaciousness of a vaccine is often measured in terms of the level of immune response generated in the body. For instance, the Oral Polio Vaccine stimulates the immune system to produce anti-poliovirus antibodies against three types of poliovirus. These antibodies will protect the body should there be an infection of poliovirus at a later stage.

In case of Covid-19 vaccines, the efficacy is measured differently. It has been little over a year that we have known about the novel coronavirus, its different strains and the disease. The immune response that the virus stimulates in human body could either be antibody-mediated or cell-mediated. Which kind of immune response is activated when and why is still being studied. Therefore, it has been not easy to measure the efficacy of Covid-19 vaccines in terms of the immune response produced.

However, a vaccine was urgently needed to contain the disease, if not to completely prevent it. Consequently, vaccine performance was measured in terms of the symptoms averted. This way, at least severe symptoms and deaths due to Covid-19 can be potentially prevented. This is the reason we hear that the vaccine does not guarantee complete protection from Covid-19 after vaccination and that it only prevents symptomatic disease. 

Limited knowledge about the behaviour of the virus and human immune response, and at a very short time in which the vaccines have been developed and tested are some of the key reasons these vaccines do not assure complete prevention of the disease. This is why these vaccines have got “emergency use approvals” in most countries and vaccination is made voluntary.

Vaccine effectiveness

Vaccine efficacy and effectiveness, both conceptually measures of a vaccine’s performance, are different in terms of the conditions in which they are measured. But these conditions may well be a deciding factor for using a vaccine in the long run.

The optimal conditions in efficacy studies are used for recruiting the participants for a vaccine trial in order for the experimental and control groups to be comparable. Depending on the aim of the trial, specific eligibility criteria such as age, setting, prior exposure could be used for creating optimal conditions during efficacy trials. These are akin to the laboratory research, which takes place in controlled or ideal conditions.

Vaccine effectiveness, however, is measured in real-world settings. Vaccines are administered at various places (primary care centres, vaccination camps and more), to people of various age groups, sex, varied levels of prior exposure, comorbidities and so on. These uncontrolled conditions give a broader, more detailed picture of vaccine performance in a range of conditions. Considering this broad array of biological, social, genetic and environmental factors, vaccine effectiveness is aimed at measuring several aspects of vaccine outcomes. 

These include (but are not limited to) differences in clinical outcomes based on personal, demographic and clinical parameters, adverse event following immunisation, cost effectiveness (disease cost vs vaccine cost), side effects and more. In other words, effectiveness is a measure of the real-world application of a laboratory experiment. In addition, because of the large sample size in effectiveness studies, it becomes a well-rounded measure of vaccine performance.

Vaccine effectiveness studies are critical in making decisions about the long-term use of vaccines.

In the case of Covid-19 vaccines, owing to the limited time period for which they have been used, effectiveness studies are rare. Much data on effectiveness of vaccines used in India is not yet available. As a result, the extent to which these vaccines are effective in the real-world settings and in the long run.

Why it matters

In a world of quick communication, readers are bombarded with information but are not always equipped to verify its authenticity. This is especially true in matters of health, which are frequently discussed but in a way that could lead to misinterpretation. These frequent misinterpretations may lead to mistrust, doubt, politicisation, vaccine hesitancy and fear. This could ultimately impact personal and public health outcomes. 

Note: Vaccine efficacy percentages are based on the currently available research. Some media reports may mention different efficacy percentages.

Dr Sumedh MK is a public health professional, currently working as a consultant with the Maharashtra government’s public health department.

This is only for your information, kindly take the advice of your doctor for medicines, exercises and so on.     

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The Lesser-Known Covid-19 Vaccines You Should Know

The vaccination campaign against Covid-19 is underway across the world, with more than 104 million doses having been administered across 66 countries, according to recent data. The vaccinations currently in use are produced by Pfizer and BioNTech, Moderna, and AstraZeneca (in collaboration with the University of Oxford). While these vaccine variations were the first ones to be authorized for mass rollout by the World Health Organization, it seems that they will soon be joined by Russia’s Sputnik V vaccine and possibly China’s two front-runner vaccines - Sinovac and Sinopharm.

What do we know about these vaccines, and how do they compare to the Pfizer, Moderna, and AstraZeneca vaccines?  

 

Sputnik V proves 92% effective in a trial 

The Russian vaccine was initially met with some controversy because it was rolled out before the completion of the final trial. The trial results recently published in the medical journal The Lancet deemed the vaccine safe and 92% effective. 

 

In a comment published alongside the paper, Professor Ian Jones and Polly Roy stated, "The development of the Sputnik V vaccine has been criticized for unseemly haste, corner-cutting, and an absence of transparency. But the outcome reported here is clear and the scientific principle of vaccination is demonstrated, which means another vaccine can now join the fight to reduce the incidence of Covid-19".

The vaccine works in a similar way to the Oxford/AstraZeneca jab developed in the UK. It exposes the body to the virus’s genetic code, which helps the immune system recognize the virus as a threat and fight it, all without the risk of becoming ill. In other words, after the vaccination, the body starts producing antibodies tailored to fight the novel coronavirus. 

 

The main difference between the Sputnik V vaccine and the AstraZeneca jab is that the former uses a slightly different formula of the vaccine in the first and second vaccination dose. This is believed to provide longer-lasting protection and helps boost the immune system more than using the same version twice. 

 

There were no severe reactions and deaths linked to the Russian vaccine during the trial. The only side effects recorded were mild - a sore arm, fatigue, and fever. 

 

The study didn’t address the shot's effectiveness against the new variants of the coronavirus. However, Russian officials have stated they are continuously testing Sputnik V against new variants, and they expect the shot to be just as potent against the new variants of the virus.

In early January, the Russian Direct Investment Fund, the organization that bankrolled the jab, said that over 1 million Russians have already been vaccinated. Outside Russia, Sputnik V has received Authorization in over a dozen countries, including Belarus, Argentina, Bolivia, Serbia, Iran, and the UAE.

What do we know about the Sinovac and Sinopharm Vaccines? 

Meanwhile, China is making great strides to become a leading vaccination provider, too. The two prominent vaccines from China are made by two companies: Sinovac and Sinopharm. The former is a private company, and the government funds the latter. Vaccines from both companies have been granted conditional approval in China. 

 

Both companies are developing inactivated vaccines that work in a similar way to Sputnik V. This is a more traditional method of vaccination, compared to the Moderna and Pfizer vaccines, which use a novel approach, mRNA. The main advantage of this tried and true form of vaccination is that it can be stored in a standard refrigerator at 2-8 degrees Celsius, while Moderna's vaccine needs to be stored at -20°C and Pfizer's vaccine requires an even lower temperature — -70°C.

This means that the Chinese and the Russian vaccines could be a lot more useful in developing countries, as they are more affordable, easy-to-transport, and don’t require advanced storage facilities.

What about their efficacy? At this point in time, it’s hard to determine. One Chinese study published in The Lancet only has information from the first and the second phase trials of Sinovac. Interim data from late-stage trials in Turkey and Indonesia showed that the vaccine was 91.25% and 65.3% effective respectively. Researchers in Brazil initially said it was 78% effective in their clinical trials, but in January of 2021, they revised that figure and stated that the vaccine was 50.4% effective after including more data in their calculations. 

 

As for Sinopharm, phase three trial results from late December showed that it was 79% effective. However, the United Arab Emirates, which approved the Sinopharm vaccine earlier this month, said that the vaccine was 86% effective, according to the interim results of their phase three trial. 

 

While there is still more information to be gathered, one thing is clear: if the world wants to take the global pandemic under control, we will need a number of vaccines to work. That’s exactly why so many eyes are trained on the Chinese and Russian candidates. The recent promising news, especially regarding the latter, is indeed cause for cautious optimism.

This is only for your information, kindly take the advice of your doctor for medicines, exercises and so on.     

https://gscrochetdesigns.blogspot.com. one can see my crochet creations  
https://gseasyrecipes.blogspot.com. feel free to view for easy, simple and healthy recipes    
https://kneereplacement-stickclub.blogspot.com. for info on knee replacement