Houston Chronicle Sunday

Facts about the Pfizer, Moderna vaccines

- By Julie Garcia STAFF WRITER

Official approval looms for pharmaceut­ical companies Pfizer and Moderna in the next few weeks as they prepare to bring COVID-19 vaccines to the public.

Vaccines typically take 10 years to develop, test and put on the market, so the speed at which both companies have produced these vaccines has prompted consumer questions: What are the side effects? Who’s first in line to get the shot? How long before we can congregate in groups without masks?

Here’s what you should know about both vaccines.

When will the vaccines be reviewed by the U.S. Food and Drug Administra­tion?

Pfizer’s vaccine will be reviewed by the FDA on Dec. 10, and Moderna will go through the same process on Dec. 17, said Dr.

Dirk Sostman, chief academic officer at Houston Methodist.

Each vaccine will require two doses, administer­ed about three to four weeks apart.

How were the vaccines developed so quickly?

The goal of Operation Warp Speed — a federal partnershi­p between the Centers of Disease Control and Prevention, the Department of Health and

Human Services, Biomedical Advanced Research and Developmen­t Authority and Department of Defense — is to produce and deliver 300 million doses, as part of a broad strategy to speed up the vaccine’s developmen­t and distributi­on.

Pfizer did not accept advance federal funding to help develop or manufactur­e the vaccine, unlike Moderna, but has a $1.95 billion deal with Operation Warp Speed once the vaccine is delivered, according to the New York Times.

How will Texas distribute the vaccine?

The federal government has left distributi­on plans up to the states. In Texas, Gov. Greg Abbott created a 17-person panel of experts to develop a distributi­on plan.

Abbott announced Tuesday that the state will receive an initial allotment of 1.4 million doses in December.

The initial doses, which could be distribute­d as early as Dec. 14, will target health care workers who have the highest exposure, like infectious disease doctors, emergency room staff, doctors and nurses who are around older patients or sick patients every day, Sostman said.

Next in line are frontline workers and at-risk health population­s, such as diabetics, cancer survivors and anyone who may be immunocomp­romised.

According to the governor’s office, the state will try to distribute the vaccine fairly regardless of demographi­cs, poverty, insurance status or geography.

When and where will the rest of the population get the vaccine?

While there is not yet a plan for distributi­ng the vaccine to Texans who don’t fall into the toppriorit­y population­s, Sostman believes most people will be able to be vaccinated by mid-2021. Vaccines will be available at CVS, Walgreens, H-E-B, Kroger and other select pharmacies.

Will it work for all ages? Do certain age groups get priority? Who should not get the vaccine yet?

Pfizer and Moderna say their vaccines are equally effective and safe in all age groups. Though there’s not much detailed data available yet, Sostman said there is no reduction in efficacy in older people.

Children under the age of 16 have not been part of most vaccine clinical trials, but Moderna announced that it would soon begin testing in children ages 12 through 17. The study will include 3,000 children, with half receiving two shots of vaccine four weeks apart, and the others receiving placebo shots of salt water.

Those trying for pregnancy should wait at least two menstrual cycles after getting the second dose of the vaccine, Sostman said. “We really don’t know whether it’s safe in pregnancy because it hasn’t been studied,” he said. Will the vaccine be free?

Senior citizens will have access to the COVID-19 vaccine “at no cost when it becomes available,” according to the Centers for Medicare and Medicaid Services.

The agency has developed resources for providers and pharmacies that can administer the vaccine to make sure they will be reimbursed through Medicare. Private insurers and Medicaid programs will be responsibl­e for covering the vaccine at no charge to beneficiar­ies, according to CMS.

Should people continue to mask up, wash their hands frequently and social distance after being vaccinated?

The responsibl­e thing to do is to continue to socially distance, wear a mask and wash your hands after getting vaccinated until more is known about what exactly the vaccine does in the body, Sostman said. “There’s a 95 percent chance that you’re not going to get sick (after being vaccinated),” Sostman said. “At this point, it’s unknown whether you can be a ‘stepping stone’ of virus from one person to another after being vaccinated. If you can still become infected with the virus, your immune system will keep you from getting sick, but you can still theoretica­lly pass it to other people.”

What are possible side effects?

Since the vaccines were developed quickly, it is possible there may be delayed allergic reactions or extraordin­arily rare reactions, Sostman said. But it is unlikely.

The site where the injection was made may hurt, the patient may feel fatigued or develop a headache, he said.

How long will immunity last after vaccinatio­n? Should we be worried about vaccine resistance if the virus mutates?

Since the coronaviru­s is more stable than the influenza virus, the vaccine against COVID-19 should be more effective than the flu shot, Sostman said.

“Based on the rate of mutation of the virus, I would guess protection would last at least a year and potentiall­y much longer,” he said, adding that it’s possible it will need to be an annual vaccinatio­n like the flu shot.

The COVID vaccines are messenger RNA, or mRNA, vaccines, which teach cells how to make a protein that triggers an immune response inside our bodies, according to the CDC. The immune response, which will produce antibodies, is what will protect the body from getting infected.

If a person has already had COVID-19 and recovered, studies show that antibodies built up from the virus go away after a couple of months. Therefore, recovered patients would need to be vaccinated like everyone else, Sostman said.

The coronaviru­s will continue to mutate, Sostman said, but the spike proteins that the mRNA vaccines are directed against seem to be stable, which means those proteins are unlikely to change.

What is herd immunity, and will it apply to the COVID vaccine?

If a high enough percentage of people in the population are immune to a disease, they’re unable to pass it on, and it tends to die out naturally.

The percentage of people required to be immune varies very much from disease to disease, but the standard answer is 70 percent.

“The basic theory is if there’s not a lot of dry wood on the forest floor, you won’t have a forest fire,” Sostman said.

The reason it’s called herd immunity is because it was first observed in cattle, he said. “They discovered if they bunched together the cattle who had a disease and recovered from it, the herd became more resistant to the disease overall, including ones that hadn’t been infected,” he said.

When will the world go back to normal?

Nobody really knows, but it depends on how many people get vaccinated, Sostman said.

“My optimistic projection is that enough of the U.S. population will either be immune because of the vaccinatio­n or immune because they got the disease by the beginning of next summer,” he said. “Life can go back to something resembling normal by the fall.”

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