There are hundreds of companies around the world that develop vaccines against pathogens but which ones are best in terms of efficacy and safety? Not all, unfortunately, have equal success with each other and there are many factors affecting these results. Some could argue that each vaccine is equally good at vaccinating people against COVID-19 so if one becomes more successful then this will be the most successful. But which vaccine is better than others? Here we look at some of the ingredients used by most of the vaccines on use.
In the case of the Pfizer/BioNTech vaccine, these ingredients were not tested very carefully and the data presented by them is based on limited information. However, when it comes to their competitors, they have been through the same test as Pfizer and have received much more testing. For example, both Johnson & Johnson (J&J) and AstraZeneca have given similar results for their respective jabs but were found to give slightly different results in two studies. Also, while J&J and AstraZeneca have shown similar levels of immunity after getting vaccinated it appears their data has not covered a large cohort of subjects and this raises questions about why.
So here’s a detailed rundown of what the Pfizer/BioNTech Covid-19 vaccine contains.
Vaccine: A combination of the whole virus that causes the illness with an adenovirus that delivers the genetic code of the spike protein into cells – causing them to create antibody responses against the actual coronavirus protein. While this may not be a 100% effective, it can give you protection against infection, particularly if you have had your own vaccination. This was found to work well against SARS-CoV2 (the virus that caused the initial spread of the disease), and also against another pathogen called MERS-CoV. Other viruses may not respond well to the Adenovirus, causing them to remain isolated for longer periods so only those who are vaccinated should contract the disease. Although both companies plan to manufacture the vaccine at scale, there is no known date for when it will be ready.
Vaccine: An immune response, produced by the body itself, against the viral protein of the coronavirus, which contains at least three copies of its spike protein, which induces the immune system to produce antibodies against it. It works by triggering the T-cells to attack the virus if they find it, rather than fighting it if they recognize it. If your body produces enough antibodies, it protects your cells, reducing transmission and even preventing your body from making new infections. After that, your lymph nodes tell your immune system to make more antibodies and this creates a “ memory” of protection and the body usually keeps producing more. Your body does this by using the antibodies to identify and destroy infected cells that have mutated and changed their outer surfaces – therefore rendering SARS-CoV-2 less susceptible to future mutations and changing its protein structure. If your immune system destroys these cells before they spread them further, it means that you have “sheddled the virus” (and spread it if any). As with any vaccine, this will be affected by individual differences, particularly if you happen to have poor or weak immune responses. It is not clear at this time when your long-term protection will come – although even if it does, the vaccine must be kept cold for at least five days or more. Many people feel ill after two weeks but this is because the vaccine takes a while to build up our immune system and over time this number may diminish.
Vaccine: Long term immunity is the main component of the vaccination programme – this lasts 12 months, at least, and can lead to longer-lasting effects. Most people are protected by the second dose which should be three-monthly and the risk of side effects should start within the next six weeks. All three doses, including the first injection, protect two full cycles of the immune system: the acute phase when your immune response is activated; and the recovery phase which involves building up the T-cells and B-cells that control inflammation and fight infection and can last four years (or, longer for women). All these cycles take around four months. Even though protection lasts for life, it is important to remember that there will always be newer variants of the virus that cause different kinds of symptoms. Because they’re harder for the immune system to combat, you should get a booster shot every 6–12 months – to keep your protection long lasting. These variations are generally harmless and do not generally pose much threat.
Vaccine: About 95% effectiveness with a maximum of 94%. Based on early data, this vaccine seems to prevent 90% of cases of symptomatic COVID-19 and 70% prevent asymptomatic cases. To see how good it is, it is crucial to compare with other vaccines – such as ChAdOx1 for example, whose effectiveness drops to 75% after just two weeks when many women suffer from fever and muscle ache within days of the second dose. It has been suggested that the Oxford University vaccine would work similarly, but research continues to support that possibility. The company has said that when comparing its findings with similar tests in other countries, it is possible that the UK is actually ahead of the pack. Both Pfizer/BioNTech and Oxford use the Adjuvanted mRNA platform where the protein is surrounded by lipid particles so it doesn’t harm the cell’s ability to send signals to the immune system. They use a chimpanzee adenovirus to deliver it to human cells where it acts as a vector to deliver the protein to the immune system that gives it temporary boost. When the jab is injected into the skin, it stimulates the immune response. It can take between 1 and 5 days for the injection to work, however, with the Moderna vaccine being administered in two-minute intervals it’s reported to be quicker and quicker. Unlike the Pfizer/BioNTech vaccine, which requires at least 21 days for the vaccination process to produce any kind of effect, research suggests that Covid-19 jabs can be delivered almost immediately and that it is highly likely they can be delivered at lower costs. So far, no side effects have been reported, but many people claim to have some pain at the injection site. It is also difficult to measure how long protection lasts – and this will be a factor in deciding which vaccine is more effective – if you’re still unvaccinated and you think you may get COVID-19, it might be better to go straight away and get vaccinated. If you’ve recently recovered from the virus and you’re looking forward to having your normal life back then the fact that you have antibodies that block the virus in your blood means that you are less likely to become reinfected. However, if you have recovered in the past week or two and you believe you are more likely to fall sick again, you should not have the vaccine at this time – it is important to know what your immune system is going through as it evolves, especially if you haven’t been following good hygiene (and you want to protect yourself) and if you haven’t been very social or social distancing. For those who do fall sick it can be tempting to have another vaccination, but some people will find themselves without protection because their immune systems are struggling and they will need to rest, eat and sleep. You certainly don’t need to have multiple jabs – many times they’ll combine in order to provide protection against the total disease, otherwise your antibodies will fade over time.
Vaccine: 95% immunity is after three months (95% protection from 10 days after the second dose), or 90% of cases of symptomatic or severe COVID-19 and 50% protection after 15 days if the disease is confirmed by PCR.
Vaccine: Two doses, spaced 3 to 4 weeks apart and at least one month between each dose. Due to limited evidence it was claimed that both doses would provide 100–90% protection with the majority of recipients of AstraZeneca claiming that this protection lasts for 16 days or longer. Pfizer/BioNTech claim the second dose provides 60–90% immunity three months later and it is claimed that both doses provide 80–90% protection after 21 days.
Vaccine: 30–90% efficacy after nine days of being completely uninfected. The German company claims the vaccine can be stored for 40 days at standard refrigerator temperatures, and unlike the Pfizer/BioNTech COVID -19 vaccine, does not require freezing. On Monday September 13, the company announced that it had applied for emergency approval from the European Medicines Agency (EMA) for a rolling review of its vaccine for COVID-19 as a preventive measure and was expected to receive authorization soon. This will allow the company to distribute its product quickly across Europe, enabling a rapid distribution once approved, making it easier to reach high priority populations in need of a vaccine, such as elderly and care home residents. It is estimated that the EU will buy 200 million doses of the AstraZeneca/Oxford vaccine, and around 190 million doses of the Chinese Sinopharm vaccine. In addition, Japan has ordered 20 million doses, Indonesia is planning 20 percent doses and Brazil will have ordered 40 percent doses. India, China and the US have already begun testing the vaccine, and these deals add to the global supply.
Vaccine: No serious side effects following two doses followed by either a placebo or standard dose of saline. The companies report that the side effects are mild or moderate and tend in the latter half. They are generally short-lived and they generally resolve within a day or two, although there sometimes a few cases of local injection site irritation and some.
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