After a year fighting the SARS-CoV-2 coronavirus, and despite the development of vaccines in record time, we now find ourselves in a difficult time. New variants of the virus have emerged that spread more effectively, and to complicate matters, vaccine companies are struggling to respond to global demand. How serious is the situation? How long will it last? We will try to shed light on these issues.
How many vaccines are being administered and where?
Currently 5 vaccines are being administered in the world, 3 of them (Pfizer, Moderna, AstraZeneca) approved by independent bodies, and the other 2 produced by state bodies in Russia and China, and administered in other countries, but without an external evaluation.
Many developed countries have already started vaccinations. But it is the countries of the European Union, which bought the vaccines en bloc, that are the furthest behind. This is because both Pfizer and Moderna have delayed their deliveries, and AstraZeneca has announced that it will deliver less than expected. As for China and Russia, in addition to vaccinating their population, they are also distributing their vaccine outside and within the European Union (as seen in table 1).
Are all the vaccines being administered equally effective?
In clinical trials, the efficacy of the vaccine is deduced based on the number of contagion events that arise when tens of thousands of people are inoculated with a placebo or the vaccine. Efficacy is defined as the percentage of protection against disease in the vaccinated group relative to the placebo group. Thus, the Pfizer vaccine has shown an average efficacy of 95% (94% in people over 65 years of age, who made up about 40% of the participants). This means that 95% of Covid-19 cases have happened in the placebo group. Moderna’s vaccine has shown an efficacy of 94.1%, very similar to that of Pfizer, although in this case only 25% of the participants were older than 65 years.
The Russian and Chinese vaccines (Sputnik V and CoronaVac) have shown an efficacy of 91.6% and 79%, respectively. The efficacy of the AstraZeneca vaccine is more difficult to calculate, as they used different doses in clinical trials and included very few people over 65 years of age. The European Medicines Agency has approved it, evaluating its effectiveness at 60% and highlighting that there is little data in people over 65 years of age.
Which countries are more advanced in the vaccination process?
The most advanced countries in vaccination are Israel (almost 60% of the population), the United Arab Emirates (almost 35%), the United Kingdom (15%), Bahrain and the United States (both around 10%). With percentages below half those of the US go the European countries and the rest of the world (following graph). Among the furthest behind are countries such as Brazil and India, with high transmission of the virus and a large part of the population in terrible social and health conditions.
The pandemic and the development of vaccines have fostered the rise of a “nationalism” whose immediate consequence is a higher percentage of the vaccinated population in countries with greater purchasing power. This further increases inequality. To alleviate these effects, the COVAX initiative of the World Health Organization has been developed, which aims to distribute 2 billion doses before the end of 2021 (1.3 billion of them to 92 low-income countries).
Are the pharmaceutical companies being able to respond to the demand?
The development of the five vaccines that are currently being administered occurred in record time. We all wondered what the next bottleneck would be, the production of the vaccine or the logistics of its distribution and inoculation.
Well, for now it seems that the problem is production. The latest news that has reached us in this regard has been disappointing. The vaccine project being developed by the prestigious Pasteur Institute in Paris in collaboration with the pharmaceutical company Merck has been abandoned due to poor results in clinical trials. The company is trying to adapt the vaccine for oral administration to increase efficacy. This leaves Europe at the expense of pharmaceutical companies Pfizer, Moderna and AstraZeneca, which are delaying their vaccine deliveries due to production problems.
This was, in part, to be expected. We are talking about vaccinating the entire world population in record time, something that has never been done before. It is normal that it takes time to set up production and distribution centers on all continents so that vaccines reach every corner.
In this regard, companies that abandon their projects (such as Sanofi, in Europe) are making their facilities available to the companies that have been more successful. In this way, production could be increased to meet demand, although there would still be ups and downs. Let us remember, without going any further, what happened to medical supplies at the beginning of the pandemic.
What vaccines will be approved in the coming months and what type are they?
Fortunately, the race to develop safe and effective vaccines has not stopped. As of today there are about 240 candidates in development. Table 2 lists the vaccines that are in Phase 3 and Phase 2/3. Some of them may be more effective, easier to keep, or cheaper.
Those that are more advanced, about to request the approval of the American and European regulatory agencies, are those of Novavax and Johnson & Johnson (J&J) in the US, and in China that of CanSino Biologics.
The Novavax vaccine is more traditional than those already approved. It consists of a stabilized form of the coronavirus protein S. One of its advantages is the storage temperature (2 to 8 ºC), which facilitates its distribution and storage as it does not require freezing (as required by mRNA vaccines). It has shown an efficacy of 89.3% in the United Kingdom, where the prevalence of the British variant was 50%. This shows that it works against that variant of the virus. Another important aspect is that protein vaccines will be able to include all variants of the virus in each dose, while mRNA vaccines will require the administration of separate doses for each variant.
J & J’s vaccine is adenovirus, similar to AstraZeneca’s. Like the Novavax, it can be kept refrigerated for two years. J&J has already used this type of platform for the development of the Ebola vaccine, approved by the European Commission. Covid-19 has shown a combined efficacy of 66% (72% in the US and 57% in South Africa, in the presence of the South African variant). In addition, it has the advantage of needing only one dose.
In Spain we have several vaccines under development, three at the CSIC, one of which, created by Dr. Mariano Esteban’s laboratory, has already passed preclinical studies (in animals) and will begin clinical trials shortly. Also very promising is the vaccine developed by Dr. Luis Enjuanes’ laboratory, based on the complete virus, which will generate a very robust protection and is likely to prevent the transmission of the virus.
But the clinical trials of this second round of vaccines are beginning to have problems, according to Dr Halperin, director of the Canadian Vaccination Center at Dalhousie University (Canada) in an article in Nature. And because? As there are already vaccines against Covid-19, the number of volunteers is decreasing. When participating in a clinical trial, it is unknown whether the dose received is treatment or placebo, and some volunteers even drop out of the studies. This can be an undesirable delay. We need the more the merrier.
In any case, everything indicates that, although not everything has been as rosy as we thought after the approval of the first vaccines, we do not have a black horizon before us either. Many more doses of existing vaccines will arrive, and there will be new vaccines that will work for variants of the virus. In a matter of a few months, we will have our elders and the most vulnerable population vaccinated, which will drastically decrease deaths. And in the meantime, with care: hygiene, distance, open air and a mask.
Matilde Cañelles López, Scientific Researcher. Science Technology and Society; María Mercedes Jiménez Sarmiento, CSIC Scientist. Systems Biochemistry of the bacterial division. Scientific communicator, Margarita Salas Biological Research Center (CIB – CSIC) and Nuria Eugenia Campillo, Senior Scientist. Medicinal Chemistry, Margarita Salas Biological Research Center (CIB – CSIC)
This article was originally published on The Conversation. Read the original.
