Will the current crop of anti-COVID 19 vaccines hold up and keep us all safe from infection?
With the existing trend of COVID-19 infections, everybody is asking whether there is a need for additional vaccine doses. The new COVID-19 variants have put into question the vaccine’s effectiveness against mutating strains of the virus.
Booster doses are given to sustain protection against prevailing diseases. Just like the vaccine for hepatitis B, for instance, the antibodies they provide may wear off with time. For the flu vaccine, boosters are provided yearly. This may also be the case for SARS-CoV2.
There is currently no clear-cut study indicating the need for booster doses of COVID-19, according to the Centers for Disease Control (CDC). Although some drug companies have made previous suggestions of lowered immunity after 6 months of immunization, this has not yet been substantiated with clear-cut recommendations for added vaccination. We need more data for this, as this would entail added costs. Is it cost-effective to add another dose for everyone? We do not have the answers yet.
The existing vaccines have proven effective in stimulating the body’s immune response against COVID-19. According to research studies, the memory B cells are able to produce antibodies once we are exposed to the virus or to its fragments. This happens at least 12 weeks after infection or after immunization.
Research also reveals that COVID-19 vaccines can protect against mutant COVID-19 strains, so there is no need to be too concerned about mutant variants being resistant to the vaccine. The Johnson & Johnson vaccine, for instance, had 73% and 82% efficacy 14 days and 28 days post-immunization against the beta variant. The Pfizer vaccine was also found to be 88% effective against the delta variant. However, boosters may be needed if an outbreak is declared.
The best way to measure whether the vaccine induces the immune system is by measuring the antibody titers of individuals. Some vaccines seem to induce antibodies better than others, but overall, the approved vaccines have proven to be effective in increasing antibody titers. If and when researchers get to know how to measure vaccine-induced immunity, the next indication that boosters may be needed are breakthrough infections in older adults who have already been vaccinated.
Older individuals over 80 years of age make lower levels of antibodies after vaccination, so their immunity may disappear sooner than that of younger individuals. They are also the most vulnerable to new viral variants. Boosters may thus be necessary for them, together with those with compromised immune systems such as chronic steroid users and cancer patients. The people may not be able to produce antibodies in adequate amounts.
COVID-19 vaccines have not yet been thoroughly tested in people receiving palliative or end-of-life care, so there is some hesitancy in giving these patients the vaccine. This is because Phase I Clinical trials for new vaccines start with young healthy volunteers who have no comorbid conditions. However, results from the COVID-19 vaccine programs in Scotland and England on Pfizer-BIONTECH and AstraZeneca suggest that both vaccines are very effective at preventing serious illness in people aged 65 years and older. People in this age group who had a COVID-19 vaccine were much less likely to be hospitalized due to COVID-19. Thus, if they can be vaccinated and they can tolerate the possible adverse effects, they could receive immunization. It would take more studies to make a more conclusive statement, but it looks like the benefits of immunization outweigh the inherent risks for those with chronic illness.