Pharmaceutical companies are currently producing and distributing vaccines that have proven to be largely effective against COVID-19 . Some of these vaccines have already been approved by and arrived in different countries around the world . These countries have started their vaccination programs against the virus .
Among these vaccines are Oxford-AstraZeneca , Pfizer-BioNTech , Moderna , Sinovac , and the Gamaleya Institute ’ s Sputnik V .
These five vaccines use two different techniques to combat the virus . The AstraZeneca , Pfizer , and Moderna vaccines use Messenger RNA ( mRNA ), a molecule complementary to DNA and a key component in a biological process known as protein synthesis . This is considered to be a relatively new method of vaccine development . Messenger RNA uses spike proteins which , when injected , will stick to cells to produce T-cells that eventually attack the virus .
Sputnik V and Sinovac , meanwhile , use an inactivated version of the virus . This method uses a modified version of the virus , such that it cannot replicate . Since the pathogen cannot replicate , this type of vaccine can be administered to the immunocompromised . The inactivated virus method has been used in producing vaccines against influenza , hepatitis A , polio , rabies , and more .
Each of the vaccines developed has its own varying efficacy rates . Efficacy rate refers to how much the disease was reduced in a group of people in a clinical trial . This differs from effectiveness , which measures how well a vaccine works when given to people outside of the clinical trial .
The highest efficacy rate among the vaccines produced is Pfizer with a 95 % efficacy rate . Moderna and Sputnik V are tied , with a 92 % efficacy rate . AstraZeneca comes next with a 63.09 % efficacy rate . Lastly , Sinovac comes with the lowest rate of a 50.4 % efficacy rate . Sinovac has been deemed not recommended for health workers by the Food and Drug Administration ( FDA ) of the Philippines .
For dosage , all five vaccines need to be taken twice , but the AstraZeneca vaccine has the longest interval between doses , with 8-12 weeks . Moderna and Sinovac tie together , with a 4-week interval . Meanwhile , dosages of the Pfizer vaccine have to be taken 3 weeks apart . Sputnik V takes the shortest out of the five , needing two weeks and a day as the interval between doses .
For refrigeration , Pfizer- BioNTech ’ s vaccine stands out from the rest , since it needs a refrigeration temperature of -80 ° to -60 ° C . Meanwhile , Moderna vaccines need to be refrigerated at -25 ° to -15 ° C . Sinovac , AstraZeneca , and the Sputnik V vaccines need to be refrigerated at 2 ° to 8 ° C .
Out of the five vaccines discussed , Pfizer was the first vaccine to secure an Emergency Use Authorization ( EUA ) worldwide , having been approved by regulators in the United Kingdom last December 2 , 2020 . The FDA of the Philippines also issued a EUA for the Pfizer vaccine last January 14 , 2021 . However , Sinovac vaccines were the first to arrive in the Philippines , having arrived on the last day of February a week after securing its own EUA . AstraZeneca followed , arriving in March . As of writing , Sinovac and AstraZeneca are the only vaccines being used in the Philippines ’ vaccination program .
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