Pfizer’s vaccine offers new hope
In a major relief to the pandemic-afflicted world, US pharma giant Pfizer announced last fortnight its Covid-19 vaccine was over 90 per cent effective in late-stage clinical trials. The news signalled a new hope for controlling the pandemic. In fact, US Health Secretary Alex Azar said if Pfizer Inc submits the positive initial data from its Covid-19 vaccine trial to health regulators as quickly as expected, the US government plans to begin vaccinating Americans in December. The mRNA (messenger Ribonucleic Acid) vaccine, developed with Germany’s BioNTech, targets spike proteins. Unlike a normal vaccine, RNA vaccines work by introducing an mRNA sequence (the molecule which tells cells what to build) which is coded for a disease-specific antigen.
Instead of using weakened forms of the Covid-19 virus to trigger a lasting immune response, mRNA vaccines use only the virus’s genetic code. While these kinds of vaccines have been used in labs and animals, this is the first time it has been licensed for use in humans. And so, the efficacy data has a larger bearing. It proves mRNA vaccines actually work in humans. It also shows companies like Moderna who’ve also been banking on the mRNA revolution, might find success with their candidate vaccines as well.
Over a three-week period, researchers administered two vaccine doses to 43,538 volunteers; around half received the vaccine, the other half placebos. Across all participants, Pfizer logged 94 total Covid-19 cases, with a 90 per cent effectiveness rate for the vaccinated group. The trial is expected to continue until 164 people develop the disease. However, the interim results, based on the observation of 94 Covid-positive volunteers, indicate that most people who contracted the disease had received a placebo. Thereby indicating that those that received the vaccine developed some sort of immunity. Pfizer is suggesting that the vaccine might be 90 per cent effective.
US will get a lion’s share
The US FDA needs follow-up data to make sure Pfizer’s vaccine isn’t harmful. The company hopes to have that ready as early as mid-November and could seek ‘emergency use’ approval from the FDA. Once it is approved, Pfizer says it can produce 50 million doses by the end of 2020 and 1.3 billion in 2021. However, each patient requires two doses, so half that number may actually receive it. Upon FDA authorisation, the United States would receive about 20 million doses of the Pfizer vaccine per month, Azar said, on a call with reporters.
Pfizer and BioNTech refused to take money from the US government as they feared government intervention may delay their work. They believed they could initiate and wrap up vaccine trials much faster without government intervention. But the Trump dispensation promised to buy 100 million doses for $1.95 billion in the event their vaccine proved successful. So, a lion’s share of the early vaccines will go to US citizens. The US would need 375 million doses to cover 75 per cent of its adult population. It is believed that Pfizer had the efficacy data for a while now. Yet, the company chose not to disclose the results before the US elections. That ultimately led President Trump to dub Pfizer a coward as it didn’t announce the results prior to the elections. But the company denied that.
However, approval isn’t the only hurdle. Pfizer’s vaccine must be stored at -94°F, which could make it extremely difficult to deliver to many places. The cold storage requirements could impede Pfizer’s ability to reach rural healthcare systems and nursing homes, or less wealthy nations, which may not have the funds for the cold chain infrastructure. Moderna’s vaccine, widely viewed as the next-most-promising candidate, can be kept at -4°F.
However, nearly 10.4 million coronavirus cases and over 241,000 fatalities have been reported since February and the US is desperately looking for a promising vaccine. Until then, President-elect Joe Biden has urged Americans to practise social distancing and wear masks.
If everything goes well, this could usher in a revolution in vaccine production the likes of which we’ve never seen before and Pfizer and BioNtech might gain emergency authorisation for their vaccine by the end of this year. Top US infectious disease expert, Anthony Fauci, also said in an interview with MSNBC that he expects the doses of the vaccine to be available for certain high priority groups in December.
On the flip side, the safety data isn’t out yet and the efficacy numbers haven’t been vetted by outside researchers. In fact, we will only have additional information by the end of November. Also, the current assessment is based on seven days of participant follow-ups. But eventually, as more days pass by, several additional participants in the study are bound to contract Covid-19 and Pfizer will have improved clarity on the long-term efficacy of its vaccine.