How effective are the COVID vaccines?
The phase 3 trials of both Pfizer and Moderna vaccines involved between 42,000 (Pfizer) and 30,000 (Moderna) people respectively. Pfizer vaccine is 95% effective and Moderna is 94.5% effective.
How many shots of COVID 19 vaccines are needed?
Both Pfizer and Modena’s COVID-19 vaccines currently in use in the USA need two shots to be effective. The interval between the two shots of Pfizer vaccine is 21days and that of Moderna is 28 days.
What happens if I miss the second shot? Is a single shot still protective?
Two shots are needed, and the second shot is required to attain immunity. Only 2 per cent of people in the trial missed their second dose so it isn’t entirely clear what happens under those circumstances.
Are there any side effects?
In the trial, both vaccines were generally well-tolerated, and an independent data monitoring committees reported no serious safety concerns.
The most common side effects from the vaccines are:
• Fatigue
• Headache
• Muscle aches
Side effects occurred during the first week after vaccination, but were most likely one or two days after receipt of the vaccine. Side effects were more frequent following the second dose and more likely to be experienced by younger, rather than older, recipients.
What is in the vaccine?
The active ingredient is messenger RNA that carries instructions for making the virus’s spike protein, which it uses to gain entry to cells. The mRNA is synthetic, not extracted from actual viruses.
The spike protein is recognized as foreign by the immune system, which mounts an attack against it. Antibodies, B cells and T cells are activated and an immune memory is also laid down which means that the immune system has learned how to defeat the pathogen and is primed to mount a swift response if it encounters the coronavirus again.
Can mRNA vaccines change the DNA of a person?
Since mRNA is active only in a cell’s cytoplasm and DNA is located in the nucleus, mRNA vaccines do not operate in the same cellular compartment that DNA is located.
mRNA never enters the nucleus where the DNA is located so it can’t alter DNA.
What happens to the mRNA in the body?
It is active for a few days then decays rapidly.
Does the vaccine work for older people?
Yes. Trial participants were aged up to 85, and the efficacy in people over 65 was 94 per cent – a tiny bit lower than the overall number but still very protective, and much higher than some vaccine experts feared.
What about other vulnerable groups?
The vaccine appears to be equally effective regardless of recipients’ age, sex and ethnicity. It has been tested extensively in people who have already had the virus and doesn’t cause any ill effects. It has also been tested in people with “stable” pre-existing conditions – also known as comorbidities – including diabetes, cancer, hepatitis B, hepatitis C and well-managed HIV. Their response was as good as anyone else’s.
Does it protect everyone?
No, and it isn’t known why some people didn’t respond to the vaccine. But a success rate of 95 per cent (Pfizer) and 94.5 per cent (Moderna) are about as good as it gets with any vaccine.
Will anyone be excluded from the vaccination?
Yes. Pregnant women and children under 16 (Pfizer) and children under 18 (Moderna) won’t be eligible, at least at first. The vaccine hasn’t been tested on pregnant women or children under 12, and there isn’t enough data on children age 12 to 15. But trials in those groups are ongoing or planned.
Can everyone else get the vaccine?
Yes, but because there are very few doses of vaccine available initially, COVID-19 vaccination will take a phased approach.
Phase 1a, includes people working in health care settings and residents of long-term care facilities.
Phase 1b, frontline essential workers and adults 75 years and older
Phase 1c, adults ages 65-74 years, people ages 16 to 64 years with high-risk medical conditions, and other essential workers.
NB: It is not known yet when people in phase 1b and 1c will get the vaccine in Minnesota. Stay tuned.
Do I need to wear a mask after receiving COVID 19 vaccine ?
Yes. CDC recommends that during the pandemic people keep wearing masks .