Pfizer Inc (New York, NY, US) has confirmed that it is developing a vaccine booster dose to protect people from Covid-19 variants and clinical trials will begin in August. Pfizer and BioNTech (Mainz, Germany) are pursuing a third dose based on evidence of greater risk of infection six months after inoculation and rising cases of the highly contagious Delta variant.
While Pfizer and BioNTech believe the third dose of their vaccine would be effective against all currently known variants, including Delta, the companies are developing an updated version of the vaccine that targets the full spike protein of the Delta variant, they stated in a July 8, 2021, press release. The first batch of mRNA has already been manufactured for clinical studies of the booster. The companies plan to pursue the US and European authorisation for the booster dose. However, Dr Anthony Fauci, the White House’s chief medical adviser, spoke more cautiously, stating on July 11, 2021, that there is no immediate need for a Covid-19 booster for fully vaccinated Americans, though he remained open to the possibility in the future. He noted that boosters extend the ‘durability’ of vaccines so that protection lasts longer, but do not relate to the overall effectiveness of the underlying vaccine.
Speaking at a BIO 2021 conference session called ‘Breaking Barriers in Vaccine Development,’ Pfizer CEO Albert Bourla stated that “so far with the variants that have emerged, we have tested against all of those and there is no variant that escapes the protection from our vaccine.” However, if an immunosuppressive variant emerges in future, “we would aim to build a vaccine against an immuno-evasive variant within 100 days.” Third shots and the emergence of further variants requiring additional vaccine manufacture will benefit pharma companies and CMOs alike.
The global prevalence of Covid-19 is still high despite significant progress being made with vaccination drives. Most countries have not vaccinated their populations to an extent that would achieve herd immunity. Several variants have been identified, which developed a short time after the virus was discovered in late 2019, therefore it is a safe assumption that further variants (and potentially variants of concern) will emerge if case numbers remain high.
Stephen Hoge, president of Moderna Inc (Cambridge, MA, US), has also stated there may be a need for a booster shot with his company’s mRNA vaccine. Table 1 below shows the publicly known manufacturing relationships for API and dose manufacture, as well as packaging of the two marketed mRNA vaccines for Covid-19. Large CMOs such as Lonza (Basel, Switzerland), Catalent (Somerset, NJ, US), Recipharm (Stockholm, Sweden) and Baxter Biopharma Solutions (Deerfield, IL, US) are heavily involved in their production, packaging, or both.
Experts including Andy Slavitt, former senior pandemic advisor to President Biden, have raised the possibility that patients that received the Johnson & Johnson (New Brunswick, NJ, US) or AstraZeneca (Cambridge, UK) recombinant vector vaccines may require an mRNA vaccine booster shot due to the increasing prevalence of the more contagious Delta coronavirus variant, which studies suggest the Pfizer vaccine offers better protection against.
Bourla continued that one of the things learned during the pandemic is ‘how you can do manufacturing in parallel with research.’ This could mark a permanent change in how pharma manufacturing is used in response to public health emergencies, he said.
According to GlobalData’s Covid-19 dashboard, there is significant variation in vaccination rates across the seven major markets (US, France, Germany, Italy, Spain and the UK) but all of them are below the required 70% completely vaccinated threshold for herd immunity. Of these markets, the UK and US have the highest percentage of their populations fully vaccinated (as shown in Figure 1).
More than 3.4bn Covid-19 vaccine doses (all types) have been administered globally as of July 11, 2021, making them one of the most administered vaccines in history. Although serious adverse effects have been reported, these have been particularly rare. It remains to be seen whether vaccine hesitancy will be reduced with increasing vaccine usage and rising delta variant infections.