Q & A Covid-19 vaccination made easy, from the Guild of St Luke, St Cosmas & St Damian

Images: Pixabay

The Guild of St Luke, St Cosmas & St Damian, Hong Kong

• Considering getting vaccinated but worried about side effects? Overloaded by information but still have many questions?
  
• Let us, the Catholic doctors help you to do a ‘factcheck’

Question 1.: Many people got COVID 19 infection even after full vaccination in the 5^th wave, does it mean that COVID vaccine cannot prevent infection by Omicron variant?

Ans: The protective effect against Omicron infection by vaccination is certain. The key is receiving booster jab and to continue infectious control and hygiene measures such as social distancing and wearing mask. 

Fact: 

• The protective effect of vaccination against Omicron infection is significantly less than that of Delta. UK study showed vaccine effectiveness of only 69% against Omicron infection, and such protection waned with time to nearly zero after 24 weeks of full vaccination. Nevertheless, vaccine effectiveness was boosted back to 69% after booster dose injection, though such protection will wane with time again. 
  
• Booster injection can largely decrease hospitalization according to latest statistics from CDC.  Vaccine efficacy against hospitalization was 91% at Two months after booster injection.  The efficacy was reduced to 78% at 4^th month of booster injection. 

References

1. Weekly epidemiological update: Omicron variant of concern (VOC) – week 2 (data as of 20 January 2022) EU/EEA https://www.ecdc.europa.eu/en/news-events/weekly-epidemiological-update-omicron-variant-concern-voc-week-2-data-20-january-2022
2. Waning 2-Dose and 3-Dose Effectiveness of mRNA Vaccines Against COVID-19–Associated Emergency Department and Urgent Care Encounters and Hospitalizations Among Adults During Periods of Delta and Omicron Variant Predominance — VISION Network, 10 States, August 2021–January 2022. CDC. https://www.cdc.gov/mmwr/volumes/71/wr/mm7107e2.htm

Ques 2: What is the use of vaccine other than preventing infection?

Ans: The major use of vaccination is prevention of severe illness apart from preventing infection.

Fact:

• In the mortality and morbidity weekly report by CDC, data on Omicron infection in Los Angeles County was analysed with similar findings. The death rate was four times higher among unvaccinated at 0.3% compared with vaccinated group of 0.07-0.08%.
  
• Vaccination can substantially reduce hospitalization, ICU admission and death apart from preventing infection.  This is reflected by the vaccination effect on prevention of severe illness, thus markedly reducing the burden on medical system and so normal medical services can be sustained.

References

1. Liu, Q., Qin, C., Liu, M., & Liu, J. (2021). Effectiveness and safety of SARS-CoV-2 vaccine in real-world studies: a systematic review and meta-analysis. Infectious diseases of poverty, 10(1), 132. https://doi.org/10.1186/s40249-021-00915-3
2. Danza, P., Koo, T. H., Haddix, M., Fisher, R., Traub, E., OYong, K., & Balter, S. (2022). SARS-CoV-2 Infection and Hospitalization Among Adults Aged ≥18 Years, by Vaccination Status, Before and During SARS-CoV-2 B.1.1.529 (Omicron) Variant Predominance – Los Angeles County, California, November 7, 2021-January 8, 2022. MMWR. Morbidity and mortality weekly report, 71(5), 177–181. https://doi.org/10.15585/mmwr.mm7105e1

Ques.3 : Can vaccine prevent transmission of virus?

Ans: Booster vaccination can reduce household transmission and risk of infection. 

Fact:  

• Vaccination is definitely effective for the first aim, but it cannot reduce transmission to household contact.  
  
• A UK study on Delta variant showed that vaccination status of infected individuals did not affect the infection rate of household contact, but vaccinated household contact had less infection, and had faster rate of viral clearance even if the individual was infected, signifying a faster recovery.  
  
• A Danish study on the transmissibility and susceptibility of Omicron infection within household found a reduction of 28% on transmissibility in booster-vaccinated host, and a reduction of 46% on susceptibility in booster-vaccinated household contact, compared with fully vaccinated group. 

References

1. ATACCC Study Investigators (2022). Community transmission and viral load kinetics of the SARS-CoV-2 delta (B.1.617.2) variant in vaccinated and unvaccinated individuals in the UK: a prospective, longitudinal, cohort study. The Lancet. Infectious diseases, 22(2), 183–195. https://doi.org/10.1016/S1473-3099(21)00648-4
2. Frederik Plesner Lyngse, Laust Hvas Mortensen, Matthew J. et tal. SARS-CoV-2 Omicron VOC Transmission in Danish Households. MedRxiv 2021.12.27.21268278;    doi: https://doi.org/10.1101/2021.12.27.21268278

Ques.4 : Is the severity of omicron infection as mild as common cold, and should go away on its own even if infected? 

Ans: The harm from Omicron should not be underestimated. 

Fact:

• EU studies found Omicron infection has 50% less hospital admission in vaccinated individuals, particularly those who had received booster dose.  The less severe natural course of Omicron is partially explained by the presence of certain immunity of the infected, either from vaccination or previous infection; and the young age of infected individuals. This leads to underestimation of severity of Omicron infection. 
  
•  The death rate in Omicron is 0.16%, 10 times higher than that in Flu (0.0163%) according to CDC figure.  
  
• The rate of severe illness increases with age, as with infection caused by other COVID variants.  Omicron is much more infectious than the previous variants, and when the incidence of infection grows exponentially, the absolute number of severe illness will be high even if the proportion of severe illness is low.

References

1. Weekly epidemiological update: Omicron variant of concern (VOC) – week 2 (data as of 20 January 2022) EU/EEA https://www.ecdc.europa.eu/en/news-events/weekly-epidemiological-update-omicron-variant-concern-voc-week-2-data-20-january-2022
2. Danza, P., Koo, T. H., Haddix, M., Fisher, R., Traub, E., OYong, K., & Balter, S. (2022). SARS-CoV-2 Infection and Hospitalization Among Adults Aged ≥18 Years, by Vaccination Status, Before and During SARS-CoV-2 B.1.1.529 (Omicron) Variant Predominance – Los Angeles County, California, November 7, 2021-January 8, 2022. MMWR. Morbidity and mortality weekly report, 71(5), 177–181. https://doi.org/10.15585/mmwr.mm7105e1
3. National Health Center for Health Statistics on Influenza, CDC. https://www.cdc.gov/nchs/fastats/flu.htm

Ques. 5: Will Omicron give more harm to children?

Ans: Omicron has less severe illness than Delta but increases the number of hospitalizations in children. Despite most infected children have mild disease course, we cannot neglect the risk of severe illness or even death. Thus, we have to do whatever we can to prevent these problems from happening.

Fact:

• From data analysis of Omicron infection, Health ministry of New York State found children aged 5-11 years and age 0-4 years had marked increase in hospital admission number of 3.3 times and 8 times respectively compared with data a month ago. 
  
• A recent US study found Omicron had a less severe disease course compared with Delta in children age below 5.  Omicron caused 3 times less than Delta in hospitalization rate, ICU admission and use of mechanical ventilation.  
  
• UK research has found that age-adjusted admission rate had no difference between Omicron and Delta infections in children aged less than 10 years.  
  
• Although Omicron infection causes less impact upon children compared with Delta, the actual admission number was higher instead.  This reflects the Omicron variant is highly infectious.  Pre-school children are less exposed to various pathogens and in turn having low natural immunity, and current data not adequate for safely vaccinate them, we can imagine that they would have higher chance getting infected. Even Omicron infection is mild in most children, the incidence of severe illness or even death can happen, as shown in recent death of children in Hong Kong.  COVID-19 infection also has unknown long term effects such as MIS-C (Multisystem Inflammatory Syndrome in Children).

References

1. Pediatric COVID-19 update: January 7, 2022. Department of Health. New York State. https://health.ny.gov/press/releases/2022/docs/pediatric_covid-19_hospitalization_report.pdf
2. MRC and UKHSA: Omicron severity risk in children​, 19 January 2022 https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1052451/S1501_Omicron_severity_2022-01-Cambridge.pdf
3. Wang, L., Berger, N. A., Kaelber, D. C., Davis, P. B., Volkow, N. D., & Xu, R. (2022). COVID infection severity in children under 5 years old before and after Omicron emergence in the US. medRxiv : the preprint server for health sciences, 2022.01.12.22269179. https://doi.org/10.1101/2022.01.12.22269179

Ques.: Is it safe to let my primary school children receive COVID-19 vaccine?

Ans: It can be concluded from scientific evidence that both Coronavac (to children aged 3 and above) and BioNTech (to children aged 5 and above) are safe. BioNTech has higher protection from infection, but bears a rare risk of myocarditis (Figure from Hong Kong in age 12-17 years after first dose was 0.00337%). 

Fact: 

Coronavac and BioNTech have updated result on research in children.  

• In Coronavac study, age group 3-17 years had seroconversion rate of 100% after receiving two doses of vaccine with same volume as in adult, and the level of antibody is even higher than that of adult, reflecting a stronger protection.  We can take reference from WHO on the protective effect of Coronavac, 51% protection from infection and 100% protection from severe illness.  29% of participants had mild to moderate side effects, and the most common one is pain at injection site. 
  
• BioNTech studied on age 5-11 who received two doses of 1/3 volume of vaccine (10ug) and found similar antibody level compared with that of adult.  Vaccine efficacy was 90.7%.  Side effects were temporary and mild, with 71% having pain at injection site.  There was no report of myocarditis. 

References

1. Han, B., Song, Y., Li, C., Yang et al. (2021). Safety, tolerability, and immunogenicity of an inactivated SARS-CoV-2 vaccine (CoronaVac) in healthy children and adolescents: a double-blind, randomised, controlled, phase 1/2 clinical trial. The Lancet. Infectious diseases, 21(12), 1645–1653. https://doi.org/10.1016/S1473-3099(21)00319-4
2. The Sinovac-CoronaVac COVID-19 vaccine: What you need to know. World Health Organization.  https://www.who.int/news-room/feature-stories/detail/the-sinovac-covid-19-vaccine-what-you-need-to-know
3. C4591007 Clinical Trial Group (2022). Evaluation of the BNT162b2 Covid-19 Vaccine in Children 5 to 11 Years of Age. The New England journal of medicine, 386(1), 35–46. https://doi.org/10.1056/NEJMoa2116298
4. Chua, G. T., Kwan, M., Chui, C. et al. (2021). Epidemiology of Acute Myocarditis/Pericarditis in Hong Kong Adolescents Following Comirnaty Vaccination. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, ciab989. Advance online publication. https://doi.org/10.1093/cid/ciab989

Ques 7.: Will vaccination by lactating mothers give harm to infants?

Ans: Lactating mothers can protect their babies from infection by means of vaccination. 

Fact: 

• There is no live virus inside all kinds of COVID-19 vaccine
  
• A study from Singapore analyzed breast milk from lactating mothers after vaccination and found 90% of breast milk did not contain any mRNA, while the highest mRNA level in the rest was 2ng/ml, i.e. 0.667% of original vaccine, and give no harm to babies.  The fact is, breast milk contains antibodies against COVID-19 with higher level of antibodies after second dose.  Antibodies coat on infants’ respiratory surface and protect them from infection. Please note  4-8% lactating mothers noted a change of colour of breast milk to bluish green, but there is no harm and breastfeeding can be continued. 

References

1. Low, J. M., Gu, Y., Ng, M., Amin, Z., Lee, L. Y., Ng, Y., Shunmuganathan, B. D., Niu, Y., Gupta, R., Tambyah, P. A., MacAry, P. A., Wang, L. W., & Zhong, Y. (2021). Codominant IgG and IgA expression with minimal vaccine mRNA in milk of BNT162b2 vaccinees. NPJ vaccines, 6(1), 105. https://doi.org/10.1038/s41541-021-00370-z
2. Bertrand, K., Honerkamp-Smith, G., & Chambers, C. D. (2021). Maternal and Child Outcomes Reported by Breastfeeding Women Following Messenger RNA COVID-19 Vaccination. Breastfeeding medicine : the official journal of the Academy of Breastfeeding Medicine, 16(9), 697–701. https://doi.org/10.1089/bfm.2021.0169

Ques.: Why do doctors recommend COVID vaccines while they may damage the brain and nervous system?

Ans: Under the current pandemic, benefits of vaccination far exceeds the risks of vaccines or any uncertainty regarding their long-term safety.

Fact:

• Historically, vaccines had been associated with serious neurological complications such as Guillain Barre syndrome (GBS), Bell’s palsy, encephalomyelitis and stroke etc. They may lead to severe neurological impairment and death. 
  
• Johnson and Johnson COVID-19 vaccine and AstraZeneca COVID-19 vaccine were rarely associated with vaccine associated immune thrombotic thrombocytopenia (3.8 cases per million), indirectly leading to stroke. Johnson and Johnson COVID-19 vaccine was rarely associated with GBS (7.8 cases per million). 
  
• As for BioNTech vaccine, the occurrence of stroke (approx. 1700 cases per million), GBS, Bell’s palsy and encephalomyelitis after vaccination wasn’t different from the background occurrence in unvaccinated individuals in the Western world. 
  
• Apart from small number of Bell’s Palsy ( 66.9 in 100,000, and 90% recovered from illness), significant risk wasn’t observed in Sinovac-CoronaVac vaccinated people. 
  
• According to local data, occurrence of acute stroke (and acute myocardial infarction) as well shows no difference between the vaccinated and unvaccinated population. 

Overall, both available vaccines in Hong Kong appear safe for the neurological system. On the contrary, contracting COVID can cause devastating neurological sequelae such as encephalopathy, stroke, cerebral venous thrombosis, encephalitis, seizure and GBS. There is no denying that the current data we have are short term and far from abundant, and uncertainties remain regarding the vaccines’ long-term safety. More importantly, we must weight against the disease transmission risk in the community, risks of getting infected and the benefits the vaccines can provide. Under the global pandemic of multiple viral variants, given the established effectiveness of the vaccines and boosters on disease prevention, benefits of vaccination far exceeds the risks of vaccines or uncertainties regarding their long-term safety. On that account, patients who suffer from epilepsy, dementia, stroke, neuromuscular and neuroinflammatory disorders are recommended to vaccinate, as long as they have been assessed by their neurologists and the disease control is fair. (PS: in the original Sinovac manufacturer leaflet, patients with severe neurological disease e.g. transverse myelitis, GBS, demyelinating disease aren’t recommended to inject Sinovac-CoronaVac. But these patients can receive BioNTech.)

References

1. Updates on Thrombosis with Thrombocytopenia Syndrome (TTS). ACIP Meeting December 16, 2021. (https://www.cdc.gov/vaccines/acip/meetings/downloads/slides-2021-12-16/02-COVID-See-508.pdf) 
2. Rosenblum HG, Hadler SC, Moulia D, et al. Use of COVID-19 Vaccines After Reports of Adverse Events Among Adult Recipients of Janssen (Johnson & Johnson) and mRNA COVID-19 Vaccines (Pfizer-BioNTech and Moderna): Update from the Advisory Committee on Immunization Practices – United States, July 2021. MMWR Morb Mortal Wkly Rep. 2021 Aug 13;70(32):1094-1099. doi: 10.15585/mmwr.mm7032e4 
3. Klein NP, Lewis N, Goddard K, et al. Surveillance for Adverse Events After COVID-19 mRNA Vaccination. JAMA. 2021;326(14):1390–1399. doi:10.1001/jama.2021.15072 
4. Barda N, Dagan N, Ben-Shlomo Y, et al. Safety of the BNT162b2 mRNA Covid-19 Vaccine in a Nationwide Setting. N Engl J Med. 2021 Sep 16;385(12):1078-1090. doi: 10.1056/NEJMoa2110475.  
5. Jabagi MJ, Botton J, Bertrand M, et al. Myocardial Infarction, Stroke, and Pulmonary Embolism After BNT162b2 mRNA COVID-19 Vaccine in People Aged 75 Years or Older. JAMA. 2022;327(1):80–82. doi:10.1001/jama.2021.21699 
6. https://www.covidvaccine.gov.hk/zh-HK/dashboard/referenceData 
7. Marsh EB, Kornberg M, Kessler K, Haq I, Patel AD, Nath A, Schierman B, Jones LK Jr; Quality Committee of the American Academy of Neurology*. COVID-19 and Vaccination in the Setting of Neurologic Disease: An Emerging Issue in Neurology. Neurology. 2021 Jul 29;97(15):720–8. 
8. CoronaVac 克爾來福接種須知 (www.coronavirus.gov.hk) 

The Guild of St Luke, St Cosmas & St Damian, Hong Kong. 2.2022