With the start of vaccination in the country, there are some doubts about which other vaccines will arrive in the coming days, how many will be from each laboratory and how they differ.
According to official information from the National Government, in February there will be 192,000 doses from the Chinese pharmaceutical company Sinovac, 100,000 from the American pharmaceutical company Pfizer directly, another 117,000 from the same laboratory, but through the Covax mechanism, and 750,000 from Oxford and AstraZeneca (also thanks to Covax).
In March, the estimate is that 2,308,000 from Sinovac, 1,750,000 from AstraZeneca (Covax) and 500,000 from Pfizer (bilateral) will arrive.
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What are their characteristics?
Pfizer – ribonucleic acid (RNA) vaccine
The technology of this vaccine has been studied for 20 years for its use in the treatment of various types of cancer. It is about the use of messenger RNA, a molecule that teaches the cells of the human body to produce a protein that makes the immune system react against SARSCov2, the virus responsible for COVID-19.
It must be stored cold to at least -70°C, and according to the US Food and Drug Administration (FDA), it is 95% effective.
“The schedule for that vaccine requires two doses. When the first dose is applied, the effect begins, but it must be reinforced with the second dose after 21 or 28 days to obtain better protection. It is important to note that it should not be mixed with other vaccines. If you have COVID-19, vaccination should be postponed, as with any other disease that causes fever,” said Dr. Fernanda Hernández, in Noticias Caracol.
As has already been seen, it is applied intramuscularly in the arm and, for now, to people over 16 years of age, so it has not been tested in minors.
Contraindications:
“The only contraindication to the use of coronavirus vaccines is having a history of a severe allergy to the products they contain.. Polyethylene glycol can be a product that generates this type of allergic reaction, but this type of phenomenon is very rare in the general population,” Jorge Alberto Cortés, infectious disease specialist at the National University Hospital, told the newscast.
People who have a history of allergies to medications such as antibiotics, bee stings, or foods can get vaccinated.
Only those who have had very severe reactions or anaphylaxis, which required hospital management, could wait for another vaccine option and should be observed for 30 minutes after the vaccine application.
According to the CDC, people who have a severe allergic reaction or an immediate allergic reaction, even if it is not serious, after receiving the first dose of the vaccine, should also not be vaccinated. You should also not receive the second dose.
An immediate allergic reaction that occurs within 4 hours after vaccination includes symptoms such as hives, swelling, or wheezing (shortness of breath).
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As for the most frequent adverse effects, Dr. Cortés comments that they are the same as those that occur with traditional vaccines: “they can be of two types. One, at the placement site, this means the arm may hurt, burn, or turn red for two days. The others are systemic adverse effects, which means that it can cause fever, general malaise or fatigue. “This can last two to three days, it is usually low intensity, but it somewhat simulates the effects that the virus produces on the body.”
At the moment, it is not advisable to administer the vaccine to pregnant women. In the case of lactating women, it can be administered if they are part of the prioritized group, such as health workers, and it is not advisable to stop breastfeeding after vaccination.
Coronavac – Sinovac
“It is a vaccine based on inactivated virus, that is, the virus undergoes physical and chemical procedures that inactivate it, but maintains its immune response capacity,” said Carlos Álvarez, infectologist and epidemiologist to Noticias Caracol.
How is it different?
Dr. Fernández mentions that one must take into account what is being compared when it is mentioned that this Chinese vaccine is only 50% effective, compared to 90% of the others: “If it is protection from developing any symptoms of COVID-19, vaccine efficacy is 50.3%. This means that half of vaccinated people will have some symptom, whether it be a headache or discomfort. But, if it is for prevent the disease from getting worse or death, the effectiveness is 100%“.
In summary, a vaccinated person can be infected, but in the end, no one will need to go to the hospital for complications or serious illness.
It should be applied in two doses 14 days apart. and its storage requirements are a plus point, since, according to the manufacturers, it can be stored in common refrigerators, as long as it is kept between 2°C and 8°C. Furthermore, according to a publication in the magazine The Lancet Infectious Diseases (Infectious Diseases), can remain stable for up to 3 years under proper storage conditions.
Regarding its adverse effects, José Oñate, president of the Colombian Association of Infectious Diseases, comments that: “They are few and are common to vaccines, such as local pain in the area of application and low-grade fevers. No adverse events have been reported”.
This vaccine began to be applied in June 2020, which has shown that it is safe and its use is authorized in healthy people from 18 years of age.
AstraZeneca
The methodology of this vaccine is one of the most traditional, using an attenuated version of the virus. According to the German Paul Ehrlich Institute (PEI), responsible for authorizing vaccines in Germany, this is based on chimpanzee flu viruses, harmless to humans. In this case, it was genetically modified to prevent it from causing infection in people and to carry the blueprints for part of the coronavirus into the body. When applied, the coronavirus spike protein begins to be produced, so that the immune system recognizes it as a threat and tries to crush it with specific antibodies. This way, when the immune system comes into contact with the real virus, it will already know what to do.
Its efficacy rate is lower, reaching 76% after the first dose and with the second, which is applied 12 weeks later, it increases to 82%.
A clinical trial found that the vaccine reduces the duration of contagion and the viral load, which could stop the transmission of the virus. It is much easier and cheaper to produce and transport, as it can survive in standard refrigerators at a temperature between 2°C and 8°C for at least six months.
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Regarding the ages at which it can be applied, the WHO recommends the use of the vaccine in people 18 years of age and older, with no maximum age limit, so it can also be administered to people over 65 years of age.
Additionally, it recommends the vaccine specifically for people with pre-existing conditions that increase the risk of severe disease progression, such as obesity, cardiovascular and respiratory diseases, and diabetes. For people living with HIV and autoimmune diseases, or who are immunocompromised, more studies are needed.
Contraindications
According to information published by the Medicines and Healthcare products Regulatory Agency of the United Kingdom, its safety has been tested in an interim analysis of combined data from four clinical trials carried out in the United Kingdom, Brazil and South Africa, thanks to which it is known what adverse effects can cause: sinjection site tenderness, injection site pain, headache, fatigue, muscle pain, malaise, fever, chills, joint pain, and nausea.
Most adverse reactions were mild to moderate in severity and usually resolved within a few days of vaccination.