There is limited data available that can be used for proper evaluation of the need for Covid-19 vaccine booster shots for the general population, said a CDC scientist.
There is pressure on American health officials by President Joe Biden to clear the booster shots for wide distribution that he wants to start in the week of September 20.
The initial endorsement of extra shots may be limited by the panel to include only vulnerable groups and health-care workers, suggested the presentation by Dr. Sara Oliver at a Centers for Disease Control and Prevention advisory group meeting.
According to Oliver, there have been several studies that have concluded that severe disease and hospitalization due to Coid-19 infection can be effectively prevented by the authorized Covid-19 vaccines but they suggested that the vaccines could be less effective in preventing infection or mild symptomatic illness.
According to Oliver’s presentation, based on several separate studies, vaccine efficacy has ranged between 39% and 84% since the first appearance of the highly contagious delta variant of coronavirus. One of the studies referenced by Oliver examined the effectiveness of the vaccines on health-care workers and first responders and found that the vaccine efficacy dropped to around 65% in July from about 90 per cent in February. Data form Israel showed that the efficacy of the Pfizer vaccine dropped to as low as 39% in that country.
According to scientists, the effectiveness of vaccines do wane over time and that the Delta variant of the coronavirus is a hardier strain and is bale to break through the waning protection created by vaccines. .
It is “important to monitor trends of effectiveness by severity of disease over time,” according to Oliver’s presentation slides.
Many of the vaccines do require multiple doses which is quite comon, noted the slides.
For example, a third dose is required after six months in the case of vaccinations for Hepatitis B and HPV.
“Vaccines that require more than one dose do not necessarily mean that annual boosters are needed,” Oliver said during the presentation.
The CDC slides suggested that the likely prioritised groups for additional shots, after booster shots are available, would by nursing home residents, health-care providers and the elderly. These were the first groups that were vaccinated in December and January.
The top priority should be to vaccinate the unvaccinated, stressed the CDC, and added that outreach to those who remain unprotected from the virus should not be affected by delivery of booster doses to vaccinated individuals.
The importance of the availability of vaccines globally was also stressed by the agency.
“Uncontrolled spread globally that could result in new variants threatens control of the pandemic everywhere,” Oliver said. In addition to distribution globally, policies on boosters should consider “equity in the U.S. population as well,” she added.
(Adapted from CNBC.com)