Will herd immunity slow the spread of the current pandemic? Will you be among the immune or susceptible populations? Session 15 of the Biosafety X Change webinar entitled, “Understanding COVID-19 Herd Immunity and Serology for HCWs” explained the basic concepts of herd immunity and discussed its implications in the context of COVID-19.
Produced by the Biorisk Management Office of the Research Institute for Tropical Medicine, the webinar’s guest speaker, Dr. Faisal Hanif, discussed how immunity to viruses can be gained naturally or artificially. Natural immunity is developed after being exposed to pathogen or, for infants, by receiving antibodies from the mother through breast milk; whereas artificial immunity is gained either by vaccination or injecting antibodies.
Herd immunity is a key concept for mitigating an epidemic. Dr. Hanif, a consultant pathologist and clinical microbiologist, noted that herd immunity is achieved when a large portion of a community becomes immune to a disease which makes the spread of the disease from person to person unlikely. Individuals who are immune to the disease will act as barriers so that those who are immunocompromised will be protected. As a result, this breaks the chain of infection and the community becomes protected.
According to him, 66% percent of a community needs to be immune in order to reach the herd immunity threshold. The path to COVID-19 herd immunity is either through vaccination or natural infection. Herd immunity created via vaccination is the better way. History shows how vaccines successfully controlled deadly contagious diseases such as smallpox, polio, rubella, and many others. Vaccines provide immunity without causing illness or resulting complications.
Through natural infection, herd immunity can be achieved when a large number of people have recovered from the disease and developed antibodies against future infection. Individuals who recovered from COVID-19 could create immunity; however, building a herd through this manner would require exposing a huge population to the virus which could also yield different outcomes such as serious complications, overwhelmed hospitals, or millions of deaths.
As it is not clear yet if infection with the COVID-19 virus makes a person immune to future infection, Dr. Hanif reiterates the observance of precautionary measures at all times. He emphasized that herd immunity does not protect every person; there would still be the 34% who are immunocompromised and can contract the virus. Until a COVID-19 vaccine is developed, it is important to follow safety protocols to reduce the risk of infection.
Dr. Hanif concludes that in a time of crisis, we decrease our fear by having a better and right understanding. The more we know about the disease, the more changes we can effect in our existing risk assessments, biorisk management mitigation control, or biosafety standards in laboratories handling emerging and reemerging infectious diseases.
Anne Marie Alto
Featured in UP Manila Healthscape (Special COVID-19 Issue No. 17, 15 October 2020)
