mRNA vaccine response stronger after fourth dose vs third
A fourth dose of a COVID-19 mRNA vaccine can boost antibodies and other immune responses to levels higher than those seen after the third dose, according to U.K. trial data.
Researchers recruited 166 adults who had received a booster dose of the Pfizer/BioNTech mRNA vaccine after two doses of either AstraZeneca’s viral vector vaccine or initial inoculation with Pfizer/BioNTech’s shots. They were randomly assigned to receive either another Pfizer/BionTech shot or Moderna’s mRNA booster as a fourth dose. Half of the participants were older than 70, and the average interval since the third shot was seven months.
Two weeks after the fourth dose, levels of antibodies targeting the spike on the coronavirus were up to twice as high as antibody levels seen four weeks after the third dose for both vaccines, regardless of initial vaccine schedule, the researchers reported in The Lancet Infectious Diseases. Responses of immune cells called T cells were significantly increased 14 days after the fourth dose compared with 28 days after the third dose, but only in participants who received three Pfizer shots followed by a Moderna booster.
What are B.C.’s current public health measures?
MASKS: Masks are not required in public indoor settings though individual businesses and event organizers can choose to require them.
Masks are also encouraged but not required on board public transit and B.C. Ferries, though they are still required in federally regulated travel spaces such as trains, airports and airplanes, and in health care settings.
GATHERINGS AND EVENTS: There are currently no restrictions on gatherings and events such as personal gatherings, weddings, funerals, worship services, exercise and fitness activities, and swimming pools.
There are also no restrictions or capacity limits on restaurants, pubs, bars and nightclubs; and no restrictions on sport activities.
CARE HOMES: There are no capacity restrictions on visitors to long-term care and seniors’ assisted living facilities, however, visitors must show proof of vaccination before visiting. Exemptions are available for children under the age of 12, those with a medical exemption, and visitors attending for compassionate visits related to end of life.
Visitors to seniors’ homes are also required to take a rapid antigen test before visiting the facility or be tested on arrival. Exemptions to testing are available for those attending for compassionate visits or end-of-life care.
Where can I get a COVID-19 test?
TESTING CENTRES: B.C.’s COVID-19 test collection centres are currently only testing those with symptoms who are hospitalized, pregnant, considered high risk or live/work with those who are high risk. You can find a testing centre using the B.C. Centre for Disease Control’s testing centre map.
If you have mild symptoms, you do not need a test and should stay home until your fever is gone. Those without symptoms do not need a test.
TAKE-HOME RAPID ANTIGEN TESTS: Eligible British Columbians over the age of 18 with a personal health number can visit a pharmacy to receive a free take-home test kit containing five COVID-19 rapid antigen tests.
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