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Busting myths about the booster dose

13 Feb 2022

  • Prof. Neelika Malavige discusses our odds in combatting the Omicron variant
By Sumudu Chamara Vaccination plays an integral part in the battle against Covid-19, and it is still the best solution scientists have come up with to control the pandemic. However, the role of vaccines has changed during the past two years – firstly, it was said that vaccination can prevent Covid-19 infections, and secondly, it was said that vaccines can prevent Covid-19-related deaths. Now, experts say that a booster dose is necessary to prevent Covid-19-related deaths and severe complications, and like a lot of other countries, Sri Lanka too is encouraging its citizens to get a booster dose. Even though this situation has prompted some to question the role and effectiveness of vaccines, according to University of Sri Jayawardenapura Immunology and Molecular Medicine Department Head Prof. Neelika Malavige, a booster dose can help prevent hospitalisations and Covid-19-related deaths, and latest data from a number of countries have shown that the protection provided by the booster dose is significantly greater than the protection provided by two vaccines. She noted that it is important to discuss the importance of the booster dose and myths associated with it, especially in a context where even Sri Lankans have shown some reluctance in getting the booster dose. She spoke about this matter during a webinar on the current status of Covid-19 and myths and facts about the vaccination process, which was organised by the Institute of Indigenous Medicine of the University of Colombo. Omicron waves Explaining the overall situation of Covid-19 in Sri Lanka, she said that what Sri Lanka identifies as the second wave, which began in around September 2020, is actually the first wave, and that the other waves that followed can be identified as the Alpha Wave, Delta Wave, and the prevailing wave during which Omicron remains the predominant variant. She stressed that the current numbers may not reflect the true situation because testing is limited, adding that there is, however, no need to test everyone and that the testing strategy has changed according to the country’s needs. “However, the positivity rate has definitely increased. If we adopted the same strategy we used in the first and second waves where we tested even asymptomatic people and contacts (of infected people), our daily caseload will easily reach 20,000. This massive spread which we can see all over the world is due to the Omicron variant. Omicron is the only variant in some countries, whereas in Sri Lanka, Omicron accounts for about 97% infections. It means that only around 3% of the cases are not caused by the Omicron variant.” Speaking of how the Omicron variant has changed the Covid-19 situation in other countries/regions, including Europe, the US, and Australia, she said that in those countries/regions, initial Covid-19 waves caused massive damage. Adding that latest data shows that the threat posed by the Omicron variant is higher than those previous waves, Prof. Malavige stressed that it is not even possible to compare the infection rates of other variants such as Alpha, Delta, and Gamma with the rates of the Omicron variant. Vaccines, and hospitalisations and deaths She added that the Omicron variant causes more hospitalisations, Intensive Care Unit (ICU) admissions, and deaths in high-risk individuals when compared with other variants. This situation, Prof. Malavige noted, raises concerns about the role and effectiveness of vaccines, especially the booster dose. She explained: “However, despite high vaccination rates in certain countries such as the US and the UK, the number of deaths remains higher, which begs the question whether vaccination is useless. A high number of Covid-19 cases can be seen even in countries that have the highest vaccination rates, and in this context, the people’s concerns about how effective vaccination is actually a valid question.” Moreover, she pointed out that even though people can die (of Covid-19-related complications) even after taking the booster dose or the initial doses, the booster dose significantly reduces the number of people dying. According to statistics presented by Prof. Malavige, the death rate among the unvaccinated is higher than that among the vaccinated. This situation applies to most age groups. Speaking of the situation in the US with regard to vaccinations and Covid-19-related deaths, she added: “When the unvaccinated people get two doses, there is a 14 times less risk of dying. But, when it comes to the booster dose, there is a 97 times less risk of dying.” Prof. Malavige further pointed out that despite various opinions about the role of vaccines, statistics provide concrete evidence to show that vaccines, especially the booster dose, are actually effective in preventing Covid-19-related deaths. Quoting Infectious Diseases Hospital (IDH) data presented by Dr. Ananda Wijewickrama last week, she noted that currently, there is nobody in the ICU or dependent on oxygen who has taken the booster dose. In addition, quoting the National Hospital of Sri Lanka (NHSL), she said that at present, except for one person who has a lot of comorbidities, there is no one in the ICU who has taken the booster dose. In addition, showing data from the Colombo District, from 21 to 31 January, she noted that even though there were 28 Covid-19-related deaths in the over =0 years age group, not a single person who had received the booster dose had died. Not only deaths; the booster dose is effective in preventing or reducing hospitalisations too. With regard to hospitalisations, showing data from the US, Prof. Malavige pointed out that hospitalisation rates in unvaccinated people are rising rapidly, while hospitalisation rates among vaccinated people are not increasing at the same speed. Hospitalisation rates among people who have got the booster dose, however, were much lower than the above-mentioned two groups. Comparing the status of vaccinations and hospitalisations in the US, Spain, France, Denmark, Ireland, and Portugal between 1 March 2020 and 9 January 2022, she noted that Portugal has the lowest hospitalisation rates among the said countries, while the US has the highest hospitalisation rates among them. Analysing these rates, she noted: “Portugal has low hospitalisation rates because 90% of the people are fully vaccinated, while 35% have received the booster dose. However, in the US, because of strong anti-vax campaigns, 12% of the over-65 years population are not vaccinated, and only 23% of the total population have received the booster dose. If we look at the overall US population, around 69 million people who are eligible to get vaccinated have not obtained a single dose, and when there are 69 million unvaccinated individuals while the Omicron variant is spreading, it will kill people. At present, Covid-19 kills over 2,000 people a day in the US.” Natural infection/immunity Speaking on whether natural infection (natural immunity) can protect people from the Omicron variant, Prof. Malavige explained that earlier, when Alpha and Delta variants were prevalent, natural infection protected people from reinfections. However, the situation has now changed, and the Omicron variant has mutated so much that it is different from previous variants. Showing statistics about reinfections in the UK, she noted that protection from reinfections following natural infection with the Omicron variant has fallen to 19%. Therefore, under the present circumstances, natural infection does not actually protect a person from reinfections, and the people are facing the risk of dying despite natural immunity. Pfizer-BioNTech vaccine as booster dose There was a time when the people were demanding the Pfizer-BioNTech vaccine while rejecting other vaccines, which could be seen in Sri Lanka as well. However, with the concerns about the necessity of a third dose, the people are now questioning how safe and effective the Pfizer-BioNTech vaccine is. Prof. Malavige spoke about this situation as well, and emphasised that available data suggests that the Pfizer-BioNTech vaccine is a safe vaccine. She pointed out that even though 5.8 million Sri Lankans including one million children have received the Pfizer-BioNTech vaccine as the booster dose, they have not reported any health issues including the incidence of myocarditis among children which some other countries have reported. She also shed some light on guidelines for the administration of the booster dose in various countries. “In the UK, the booster dose is administered on every person over the age of 16 and it is given three months after the second dose. In the US, every person over the age of 12 receives the booster dose five months after the second dose. In Australia, every person over the age of 16 receives the booster dose, and it is usually given three months after the second dose. In Singapore, every person over the age of 12 receives the booster dose five months after the second dose. However, those above the age of 60 receive three doses of vaccines before receiving the fourth dose which is considered the booster dose. In Malaysia,the booster dose is given to every person over the age of 18, and it is given three months after the second dose. In Dubai, every person receives two doses of the Pfizer-BioNTech vaccine three months after the second dose of Sinhopharm and/or Sinovac. The minimum age to get the booster dose is 16 years.” She further noted the importance of understanding the difference between the booster dose and an additional dose. As per the World Health Organisation (WHO) definitions, booster doses are administered to a vaccinated population that has completed a primary series (currently one or two doses of emergency use listing (EUL) Covid-19 vaccine depending on the product) when, with time, the immunity and clinical protection has fallen below a rate deemed sufficient in that population. The objective of the booster dose is to restore vaccine effectiveness from that deemed no longer sufficient. Additional dose of a vaccine may be needed as part of an extended primary series for target populations where the immune response rate following the standard primary series is deemed insufficient. The objective of an additional dose in the primary series is to enhance the immune response to establish a sufficient level of effectiveness against a disease. In particular, immunocompromised individuals often fail to mount a protective immune response after a standard primary series, but also older adults may respond poorly to a standard primary series with some vaccines.  Misconceptions Moreover, Prof. Malavige extensively spoke about some of the misconceptions about using the Pfizer-BioNTech vaccine as the booster dose. Speaking of the misconception that the Pfizer-BioNTech vaccine can cause heart attacks, she said that heart attacks are the main cause of deaths in Sri Lanka. The data she presented showed that in 2019 (before the pandemic), the total number of deaths due to heart attacks was 145,475 (398 deaths per day), while the total number of deaths due to strokes in the same year was 60,757 (166 per day). She noted that because a lot of people die of heart attacks every day in the country, they are often attributed to the Pfizer-BioNTech vaccine and that such deaths happen irrespective of the vaccine.  She noted that according to studies, a lot of people, however, got heart attacks in the context of Covid-19. In the absence of vaccination, she said Covid-19 can cause a number of other diseases, and Covid-19 is associated with blood clotting. She emphasised that vaccines actually prevent the Covid-19 virus from disseminating. Another misconception Prof. Malavige spoke about was that the Pfizer-BioNTech vaccine causes infertility.  She emphasised: “According to the available data, it is Covid-19 that acts as a risk factor for new onset erectile dysfunctions, not vaccines. Studies have also found that a temporary sperm count drop is possible after Covid-19 infection.” The Pfizer-BioNTech vaccine being harmful to pregnant mothers is another misconception she spoke about.  “Last year, over 60 pregnant women died of Covid-19. Covid-19 vaccination during pregnancy has no increased risk of miscarriage, preterm births, stillbirths, or congenital abnormalities (abnormalities of body structure or function that are present at birth).” With regard to misconceptions about vaccines, she further spoke about the anti-vax movement in Sri Lanka. She said that there is also an anti-vax movement in Sri Lanka, even though there was no such thing in the country before the emergence of Covid-19. She expressed concerns that a considerable number of people, including certain medical professionals, rely on information obtained from unverified sources such as social media platforms when discussing the necessity of vaccines, and that a lot of people who oppose vaccination have various other interests. While the effectiveness of Covid-19 vaccines is still being studied, available data shows that vaccination, especially the booster dose, can prevent severe complications as well death in most cases. In a context where no medicine or vaccine can guarantee 100% safety from an illness, it is advisable to analyse the available data, and make fact and experience-based decisions regarding getting vaccinated – not rumour and assumption-based decisions.


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