Anti-Covid-19 pills: new weapons to fight the virus

Treatments to deal with the pandemic that has killed more than five million people worldwide have so far focused primarily on vaccines.

Pharmacists have conducted research to create other weapons to combat Covid and finally, after months of studies and clinical trials, Merck and Pfizer have found their “golden fleece”: innovative antiviral pills against the disease.

Merck launched first with Molnupiravir, in October, and Pfizer had the second success in early November with its anti-covid pill, Paxlovid.

Both pills are seen as a game changer to counter the effects of the pandemic, giving new hope for people who are at risk of developing serious diseases and the possibility of alleviating overburdened healthcare systems around the world.

Molnupiravir – the first antiviral drug for covid

Originally, the pill was developed to treat influenza and designed to introduce errors into the genetic code of the virus, preventing the infection from spreading in the body.

According to clinical trials in the United States, Molnupiravir, produced by Merck and Ridgeback Biotherapeutics, showed that a five-day course of the drug reduced hospitalization or death by 50% in people with mild to moderate COVID.

Also, for those with at least one risk factor for developing serious diseases such as obesity, diabetes mellitus, heart disease or those over 60 years of age.

Merck Vice President of Infectious Disease Discovery Daria Hazuda said: “This antiviral treatment is a very important tool to help people who are not vaccinated or who are less responsive to immunity from vaccines.”

The trial results suggest that Molnupiravir must be taken once symptoms develop to have an effect. Patients who had already been hospitalized with severe covid showed a disappointing response, according to a previous study.

How does this medicine work?

Once the patient is diagnosed with the disease, he can start a Molnupiravir treatment, that is, four 200-milligram capsules, twice a day, for five days, a total of 40 pills.

The drug is most effective in the early stages of infection; therefore, it is recommended to take it as soon as someone tests positive for COVID and within five days after symptoms appear.

Unlike vaccines, which target the spike protein of the virus, this antiviral works by targeting an enzyme that the pathogen uses to make copies of itself.

Vaccines elicit an immune response, while Molnupiravir disrupts the replication of the virus, causing it to produce unhealthy “babies,” so to speak.

The infection could be treated with this pill immediately after a positive test rather than waiting to see if the patient becomes seriously ill.

The Merck pill can be taken at home, freeing up hospital resources for more seriously ill patients.

A few weeks ago, the UK drug regulator gave the green light to Molnupiravir, becoming the first to approve an antiviral against Covid-19.

This movement opens the door for tens of thousands of vulnerable people to receive therapy starting this coming winter.

At the end of November, half a million doses of the antiviral would have been administered, with the elderly and people with weakened immune systems, the priority to take the pill.

This week, the European Medicines Agency EMA has advised its member states that they can use Molnupiravir – Lagevrio in Europe – in emergency situations.

Rising infection rates and deaths due to Covid-19 triggered this movement across the continent.

Covid cases are currently spiraling in several European countries, including Germany, the Netherlands, Austria and Hungary, leading governments to fear a difficult winter ahead to reimpose restrictions.

As a warning, the EMA said that pregnant women or women who are not using contraception and could become pregnant should not use Molnupiravir, as it can affect the growth and development of the fetus.

Paxlovid – antiviral pill developed by Pfizer

In the first days of November, Pfizer announced the first-line results of its trial that claimed that an interim analysis showed that its pill reduced the risk of death and hospitalization by 89% in patients who were recently diagnosed with the coronavirus.

With this antiviral, people have more time and access to treatment that will keep them out of the hospital.

The drug should be taken only if someone tests positive for COVID and within the first five days when symptoms appear.

Paxlovid must be combined with an older medicine called Ritonavir. Pfizer’s pill combines a new molecule developed specifically to inactivate SARS-CoV-2, the causative agent of Covid-19, and Ritonavir, an HIV drug that helps slow the breakdown of the coronavirus-specific drug.

Comparison between both pills

Researchers have compared Merck and Pfizer drugs, even though both data are only in press releases.

Pfizer’s pill numbers look impressive when compared to Merck’s, which is 50 percent.

Outside scientists have also raised questions about whether Merck’s drug could change patients’ DNA, which, in theory, could lead to birth defects or cancer risk.

In this sense, Merck has insisted that Molnupiravir is not likely to cause such changes based on animal studies that the pharmaceutical company has carried out. An expert panel convened by the FDA (United States Food and Drug Administration) evaluated the drug on November 30.

On potential adverse effects on patients’ DNA, a Pfizer representative said the company developed a protease inhibitor to prevent any DNA damage.

He also mentioned that Pfizer would not have stopped if its drug had only reached 50% effectiveness, as its target was higher.

License agreements

The question that remains now is whether poor countries will suffer the same fate as with vaccines. Will the pills be available to everyone, even countries in need?

Many are pondering whether wealthy nations will have preferential access to pills, as with vaccines, leaving low-income countries in second or third place.

A couple of weeks ago, Pfizer announced that it signed an agreement to allow global access to its Covid-19 pill, Paxlovid.

The deal was made with Medicines Patent Pool, a United Nations-backed healthcare organization, which gave generic manufacturers the green light to make the pill widely available in 95 low- and middle-income countries, reaching 53% of the total. world population.

In a statement, the company said: “Pfizer will not receive royalties on sales in low-income countries and will further waive royalties on sales in all countries covered by the agreement as long as Covid-19 remains classified as an emergency of Public Health of International Importance by the World Health Organization “.

Medicines Patent Pool has also entered into a licensing agreement with Merck and Ridgeback Biotherapeutics, focused on broader access to Molnupiravir in 105 low- and middle-income countries.

Regarding royalties, Merck and Ridgeback Biotherapeutics said they will not take any for sales, as long as Covid-19 remains a public health emergency of international concern in the WHO category.

What do Covid pills mean for vaccines?

Experts agree that vaccines are still the best defense and can reduce the risk of contracting Covid-19.

The pill is useful in places where vaccination rates are slow or where millions have not been inoculated. In addition, where the storage of vaccines is not possible since some of them require quite low temperatures to be effective.

One downside to the tablet is that some people may assume they are already immunized with the pill, fueling skepticism towards the vaccine and making it difficult to persuade anti-vaccines.

Oral antivirals are also protection against Covid-19, and the advantage is that they are taken orally outside of a hospital, alleviating the burden on the healthcare system to some extent.

There is always the possibility of thinking that this drug is a much better solution than a vaccine, which is incorrect. Pills and vaccines serve different purposes.

Both the pills, Molnupiravir and Paxlovid, change the rules of the game, but they are not replacements for vaccines. Vaccines are the best way to build immunity and stay safe from the virus.

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